FNB refuse to return my money

A debit order came off my account that I did not authorise and I have been emailing, phoning and waiting in queues during my lunch hour (to be mostly ignored, I might add) to have this reversed and after two weeks nothing has been done. I received an email two weeks ago ensuring action would be taken within 5 business days, which in my opinion is too long to wait for a bank to return money they had no right to remove. It has now been TEN days and I have not heard a thing and no money has been returned. Disgusting service.