diff --git a/src/.env.example b/src/.env.example
--- a/src/.env.example
+++ b/src/.env.example
@@ -96,3 +96,6 @@
 MIX_PUSHER_APP_CLUSTER="${PUSHER_APP_CLUSTER}"
 
 JWT_SECRET=
+
+KB_ACCOUNT_DELETE=
+KB_ACCOUNT_SUSPENDED=
diff --git a/src/app/Console/Development/TemplateRender.php b/src/app/Console/Development/TemplateRender.php
new file mode 100644
--- /dev/null
+++ b/src/app/Console/Development/TemplateRender.php
@@ -0,0 +1,37 @@
+<?php
+
+namespace App\Console\Development;
+
+use Illuminate\Console\Command;
+
+class TemplateRender extends Command
+{
+    /**
+     * The name and signature of the console command.
+     *
+     * @var string
+     */
+    protected $signature = 'template:render {template}';
+
+    /**
+     * The console command description.
+     *
+     * @var string
+     */
+    protected $description = "Render a email template.";
+
+    /**
+     * Execute the console command.
+     *
+     * @return mixed
+     */
+    public function handle()
+    {
+        $template = $this->argument('template');
+        $template = str_replace('/', '\\', $template);
+
+        $class = '\\App\\' . $template;
+
+        echo $class::fakeRender();
+    }
+}
diff --git a/src/app/Mail/NegativeBalance.php b/src/app/Mail/NegativeBalance.php
new file mode 100644
--- /dev/null
+++ b/src/app/Mail/NegativeBalance.php
@@ -0,0 +1,69 @@
+<?php
+
+namespace App\Mail;
+
+use App\User;
+use App\Utils;
+use Illuminate\Bus\Queueable;
+use Illuminate\Mail\Mailable;
+use Illuminate\Queue\SerializesModels;
+
+class NegativeBalance extends Mailable
+{
+    use Queueable;
+    use SerializesModels;
+
+    /** @var \App\User A user (account) that is behind with payments */
+    protected $account;
+
+
+    /**
+     * Create a new message instance.
+     *
+     * @param \App\User $account A user (account)
+     *
+     * @return void
+     */
+    public function __construct(User $account)
+    {
+        $this->account = $account;
+    }
+
+    /**
+     * Build the message.
+     *
+     * @return $this
+     */
+    public function build()
+    {
+        $user = $this->account;
+
+        $subject = \trans('mail.negativebalance-subject', ['site' => \config('app.name')]);
+
+        $this->view('emails.negative_balance')
+            ->subject($subject)
+            ->with([
+                    'site' => \config('app.name'),
+                    'subject' => $subject,
+                    'username' => $user->name(true),
+                    'supportUrl' => \config('app.support_url'),
+                    'walletUrl' => Utils::serviceUrl('/wallet'),
+            ]);
+
+        return $this;
+    }
+
+    /**
+     * Render the mail template with fake data
+     *
+     * @return string HTML output
+     */
+    public static function fakeRender(): string
+    {
+        $user = new User();
+
+        $mail = new self($user);
+
+        return $mail->build()->render();
+    }
+}
diff --git a/src/app/Mail/PasswordReset.php b/src/app/Mail/PasswordReset.php
--- a/src/app/Mail/PasswordReset.php
+++ b/src/app/Mail/PasswordReset.php
@@ -2,10 +2,12 @@
 
 namespace App\Mail;
 
+use App\User;
 use App\VerificationCode;
 use Illuminate\Bus\Queueable;
 use Illuminate\Mail\Mailable;
 use Illuminate\Queue\SerializesModels;
+use Illuminate\Support\Str;
 
 class PasswordReset extends Mailable
 {
@@ -54,4 +56,25 @@
 
         return $this;
     }
+
+    /**
+     * Render the mail template with fake data
+     *
+     * @return string HTML output
+     */
+    public static function fakeRender(): string
+    {
+        $code = new VerificationCode([
+                'code' => Str::random(VerificationCode::CODE_LENGTH),
+                'short_code' => VerificationCode::generateShortCode(),
+        ]);
+
+        $code->user = new User([
+              'email' => 'test@' . \config('app.domain'),
+        ]);
+
+        $mail = new self($code);
+
+        return $mail->build()->render();
+    }
 }
diff --git a/src/app/Mail/SignupVerification.php b/src/app/Mail/SignupVerification.php
--- a/src/app/Mail/SignupVerification.php
+++ b/src/app/Mail/SignupVerification.php
@@ -6,6 +6,7 @@
 use Illuminate\Bus\Queueable;
 use Illuminate\Mail\Mailable;
 use Illuminate\Queue\SerializesModels;
+use Illuminate\Support\Str;
 
 class SignupVerification extends Mailable
 {
@@ -60,4 +61,27 @@
 
         return $this;
     }
+
+    /**
+     * Render the mail template with fake data
+     *
+     * @return string HTML output
+     */
+    public static function fakeRender(): string
+    {
+        $code = new SignupCode([
+                'code' => Str::random(SignupCode::CODE_LENGTH),
+                'short_code' => SignupCode::generateShortCode(),
+                'data' => [
+                    'email' => 'test@' . \config('app.domain'),
+                    'first_name' => 'Firstname',
+                    'last_name' => 'Lastname',
+                ],
+        ]);
+
+
+        $mail = new self($code);
+
+        return $mail->build()->render();
+    }
 }
diff --git a/src/app/Mail/SuspendedDebtor.php b/src/app/Mail/SuspendedDebtor.php
new file mode 100644
--- /dev/null
+++ b/src/app/Mail/SuspendedDebtor.php
@@ -0,0 +1,77 @@
+<?php
+
+namespace App\Mail;
+
+use App\User;
+use App\Utils;
+use Illuminate\Bus\Queueable;
+use Illuminate\Mail\Mailable;
+use Illuminate\Queue\SerializesModels;
+
+class SuspendedDebtor extends Mailable
+{
+    use Queueable;
+    use SerializesModels;
+
+    /** @var \App\User A suspended user (account) */
+    protected $account;
+
+
+    /**
+     * Create a new message instance.
+     *
+     * @param \App\User $account A suspended user (account)
+     *
+     * @return void
+     */
+    public function __construct(User $account)
+    {
+        $this->account = $account;
+    }
+
+    /**
+     * Build the message.
+     *
+     * @return $this
+     */
+    public function build()
+    {
+        $user = $this->account;
+
+        $subject = \trans('mail.suspendeddebtor-subject', ['site' => \config('app.name')]);
+
+        $moreInfo = null;
+        if ($moreInfoUrl = \config('app.kb.account_suspended')) {
+            $moreInfo = \trans('mail.more-info-html', ['href' => $moreInfoUrl]);
+        }
+
+        $this->view('emails.suspended_debtor')
+            ->subject($subject)
+            ->with([
+                    'site' => \config('app.name'),
+                    'subject' => $subject,
+                    'username' => $user->name(true),
+                    'cancelUrl' => \config('app.kb.account_delete'),
+                    'supportUrl' => \config('app.support_url'),
+                    'walletUrl' => Utils::serviceUrl('/wallet'),
+                    'moreInfo' => $moreInfo,
+                    'days' => 14 // TODO: Configurable
+            ]);
+
+        return $this;
+    }
+
+    /**
+     * Render the mail template with fake data
+     *
+     * @return string HTML output
+     */
+    public static function fakeRender(): string
+    {
+        $user = new User();
+
+        $mail = new self($user);
+
+        return $mail->build()->render();
+    }
+}
diff --git a/src/config/app.php b/src/config/app.php
--- a/src/config/app.php
+++ b/src/config/app.php
@@ -236,4 +236,12 @@
         'View' => Illuminate\Support\Facades\View::class,
 
     ],
+
+    // Locations of knowledge base articles
+    'kb' => [
+        // An article about suspended accounts
+        'account_suspended' => env('KB_ACCOUNT_SUSPENDED'),
+        // An article about a way to delete an owned account
+        'account_delete' => env('KB_ACCOUNT_DELETE'),
+    ],
 ];
diff --git a/src/resources/lang/en/mail.php b/src/resources/lang/en/mail.php
--- a/src/resources/lang/en/mail.php
+++ b/src/resources/lang/en/mail.php
@@ -13,6 +13,11 @@
     'header' => "Dear :name,",
     'footer' => "Best regards,\nYour :site Team",
 
+    'negativebalance-subject' => ":site Payment Reminder",
+    'negativebalance-body' => "It has probably skipped your attention that you are behind on paying for your :site account. "
+        . "Consider setting up auto-payment to avoid messages like this in the future.\n\n"
+        . "Settle up to keep your account running.",
+
     'passwordreset-subject' => ":site Password Reset",
     'passwordreset-body' => "Someone recently asked to change your :site password.\n"
         . "If this was you, use this verification code to complete the process: :code.\n"
@@ -22,4 +27,16 @@
     'signupcode-subject' => ":site Registration",
     'signupcode-body' => "This is your verification code for the :site registration process: :code.\n"
         . "You can also click the link below to continue the registration process:",
+
+    'suspendeddebtor-subject' => ":site Account Suspended",
+    'suspendeddebtor-body' => "You have been behind on paying for your :site account "
+        ."for over :days days. Your account has been suspended.",
+    'suspendeddebtor-middle' => "Settle up now to reactivate your account.",
+    'suspendeddebtor-cancel' => "Don't want to be our customer anymore? "
+        . "Here is how you can cancel your account:",
+
+    'support' => "Special circumstances? Something wrong with a charge?\n"
+        . " :site Support is here to help:",
+
+    'more-info-html' => "See <a href=\":href\">here</a> for more information.",
 ];
diff --git a/src/resources/views/emails/negative_balance.blade.php b/src/resources/views/emails/negative_balance.blade.php
new file mode 100644
--- /dev/null
+++ b/src/resources/views/emails/negative_balance.blade.php
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<html lang="{{ str_replace('_', '-', app()->getLocale()) }}">
+    <head>
+        <meta charset="utf-8">
+    </head>
+    <body>
+        <p>{{ __('mail.header', ['name' => $username]) }}</p>
+
+        <p>{{ __('mail.negativebalance-body', ['site' => $site]) }}</p>
+        <p><a href="{{ $walletUrl }}">{{ $walletUrl }}</a></p>
+
+@if ($supportUrl)
+        <p>{{ __('mail.support', ['site' => $site]) }}</p>
+        <p><a href="{{ $supportUrl }}">{{ $supportUrl }}</a></p>
+@endif
+
+        <p>{{ __('mail.footer', ['site' => $site, 'appurl' => config('app.url')]) }}</p>
+    </body>
+</html>
diff --git a/src/resources/views/emails/suspended_debtor.blade.php b/src/resources/views/emails/suspended_debtor.blade.php
new file mode 100644
--- /dev/null
+++ b/src/resources/views/emails/suspended_debtor.blade.php
@@ -0,0 +1,24 @@
+<!DOCTYPE html>
+<html lang="{{ str_replace('_', '-', app()->getLocale()) }}">
+    <head>
+        <meta charset="utf-8">
+    </head>
+    <body>
+        <p>{{ __('mail.header', ['name' => $username]) }}</p>
+
+        <p>{{ __('mail.suspendeddebtor-body', ['site' => $site, 'days' => $days]) }} {!! $moreInfo !!}</p>
+        <p>{{ __('mail.suspendeddebtor-middle') }}</p>
+        <p><a href="{{ $walletUrl }}">{{ $walletUrl }}</a></p>
+
+@if ($supportUrl)
+        <p>{{ __('mail.support', ['site' => $site]) }}</p>
+        <p><a href="{{ $supportUrl }}">{{ $supportUrl }}</a></p>
+@endif
+@if ($cancelUrl)
+        <p>{{ __('mail.suspendeddebtor-cancel') }}</p>
+        <p><a href="{{ $cancelUrl }}">{{ $cancelUrl }}</a></p>
+@endif
+
+        <p>{{ __('mail.footer', ['site' => $site, 'appurl' => config('app.url')]) }}</p>
+    </body>
+</html>
diff --git a/src/tests/Unit/Mail/NegativeBalanceTest.php b/src/tests/Unit/Mail/NegativeBalanceTest.php
new file mode 100644
--- /dev/null
+++ b/src/tests/Unit/Mail/NegativeBalanceTest.php
@@ -0,0 +1,43 @@
+<?php
+
+namespace Tests\Unit\Mail;
+
+use App\Mail\NegativeBalance;
+use App\User;
+use Tests\TestCase;
+
+class NegativeBalanceTest extends TestCase
+{
+    /**
+     * Test email content
+     *
+     * @return void
+     */
+    public function testBuild()
+    {
+        $user = new User();
+
+        \config([
+                'app.support_url' => 'https://kolab.org/support',
+        ]);
+
+        $mail = new NegativeBalance($user);
+        $html = $mail->build()->render();
+
+        $walletUrl = \App\Utils::serviceUrl('/wallet');
+        $walletLink = sprintf('<a href="%s">%s</a>', $walletUrl, $walletUrl);
+        $supportUrl = \config('app.support_url');
+        $supportLink = sprintf('<a href="%s">%s</a>', $supportUrl, $supportUrl);
+
+        $appName = \config('app.name');
+
+        $this->assertSame("$appName Payment Reminder", $mail->subject);
+        $this->assertStringStartsWith('<!DOCTYPE html>', $html);
+        $this->assertTrue(strpos($html, $user->name(true)) > 0);
+        $this->assertTrue(strpos($html, $walletLink) > 0);
+        $this->assertTrue(strpos($html, $supportLink) > 0);
+        $this->assertTrue(strpos($html, "behind on paying for your $appName account") > 0);
+        $this->assertTrue(strpos($html, "$appName Support") > 0);
+        $this->assertTrue(strpos($html, "$appName Team") > 0);
+    }
+}
diff --git a/src/tests/Unit/Mail/SuspendedDebtorTest.php b/src/tests/Unit/Mail/SuspendedDebtorTest.php
new file mode 100644
--- /dev/null
+++ b/src/tests/Unit/Mail/SuspendedDebtorTest.php
@@ -0,0 +1,52 @@
+<?php
+
+namespace Tests\Unit\Mail;
+
+use App\Mail\SuspendedDebtor;
+use App\User;
+use Tests\TestCase;
+
+class SuspendedDebtorTest extends TestCase
+{
+    /**
+     * Test email content
+     *
+     * @return void
+     */
+    public function testBuild()
+    {
+        $user = new User();
+
+        \config([
+                'app.support_url' => 'https://kolab.org/support',
+                'app.kb.account_suspended' => 'https://kb.kolab.org/account-suspended',
+                'app.kb.account_delete' => 'https://kb.kolab.org/account-delete',
+        ]);
+
+        $mail = new SuspendedDebtor($user);
+        $html = $mail->build()->render();
+
+        $walletUrl = \App\Utils::serviceUrl('/wallet');
+        $walletLink = sprintf('<a href="%s">%s</a>', $walletUrl, $walletUrl);
+        $supportUrl = \config('app.support_url');
+        $supportLink = sprintf('<a href="%s">%s</a>', $supportUrl, $supportUrl);
+        $deleteUrl = \config('app.kb.account_delete');
+        $deleteLink = sprintf('<a href="%s">%s</a>', $deleteUrl, $deleteUrl);
+        $moreUrl = \config('app.kb.account_suspended');
+        $moreLink = sprintf('<a href="%s">here</a>', $moreUrl);
+
+        $appName = \config('app.name');
+
+        $this->assertSame("$appName Account Suspended", $mail->subject);
+        $this->assertStringStartsWith('<!DOCTYPE html>', $html);
+        $this->assertTrue(strpos($html, $user->name(true)) > 0);
+        $this->assertTrue(strpos($html, $walletLink) > 0);
+        $this->assertTrue(strpos($html, $supportLink) > 0);
+        $this->assertTrue(strpos($html, $deleteLink) > 0);
+        $this->assertTrue(strpos($html, "You have been behind on paying for your $appName account") > 0);
+        $this->assertTrue(strpos($html, "over 14 days") > 0);
+        $this->assertTrue(strpos($html, "See $moreLink for more information") > 0);
+        $this->assertTrue(strpos($html, "$appName Support") > 0);
+        $this->assertTrue(strpos($html, "$appName Team") > 0);
+    }
+}