diff --git a/mail.php b/mail.php
index 3a0440f..0564237 100755
--- a/mail.php
+++ b/mail.php
@@ -44,7 +44,7 @@
     $mime->setTXTBody($message->text);
     $mime->setHTMLBody($message->html);
     if ($user && $user->invoice) {
-        $mime->addAttachment ( $user->invoice , 'application/pdf' , $SERVICE_ACRONYM."-invoice.pdf" , false, "base64" );
+        $mime->addAttachment ( $user->invoice , 'application/pdf' , "invoice-".$SERVICE_ACRONYM."-" . $user->id . ".pdf" , false, "base64" );
     }
 
     $body = $mime->get();