Ask them politely being a professional human being.. if they don't.. visit the labor ministry and register a complain about them. Don't let those slave minded employers to take your right. Be confident, Ministry will support you and you will get your final settlement as your the Labor Laws in Qatar. However just make your sure you have all the necessary documents to validate your claim. Like copy of your resignation letter or email, copy of the request you made to get your final settlement etc.