grrrrr

sites/all/modules/gui/materiobasemod/materio_user.module

@@ -661,7 +661,8 @@ function materio_user_get_role_by_name($name) {
 function materio_user_mandrill_mailsend_result($result) {
   if ( in_array($result['status'], array('rejected', 'invalid', 'error')) ) {
     // remove email from pool
-    // simplenews_delete_spool(['mail'=>$result['email']]);
+    module_load_include('inc', 'simplenews', 'includes/simplenews.mail');
+    simplenews_delete_spool(['mail'=>$result['email']]);
 
     if ( in_array($result['status'], array('invalid')) ) {
       // unsubscribe user if mail does not exists