dear brother, please do not get depressed and sad, you can go to uae labor department and try to talk to the director there and tell him that this person is not allowing you to pray. i am sure that you will find some one who would help you and they will call the employer and warn him. inshaALLAH you will be heard and ALLAh swt know the niyat and your heart. so pray to ALLAH and i am sure you will get the reward from HIM.
i wish i was in dubai, i would have surely gone to the labor department and let them know.