$result = plgSystemAntispambycleantalk::onSpamCheck(
            '',
            array(
                'sender_email' => $contact_email, 
                'sender_nickname' => $contact_nickname, 
                'message' => $contact_message
            ));

        if ($result !== true) {
            JError::raiseError(503, $this->_subject->getError());
        }