1) Qatar is a Muslim country and Shariah takes precedence. That means even in the 'corporate' realm, one's religious convictions are allowed. No employer is to stop employees from dressing Islamically. If the OP reported this, his employer would be in some really hot water. Abayas, thobes, beards and ankle length trousers are all allowed in the workplace. Right from QP to cafeterias. These changes can be expected of him in the West; not here. Get with the program. It's a perfectly reasonable one.

2) To the OP: stick to your guns; if they find reason to get rid of you; well, it's probably best for you anyway. best of luck.