If you're unable to activate or make FaceTime calls, try turning FaceTime off and on again using the following:
Note: FaceTime may not be available on devices purchased or used in certain countries, including Saudi Arabia and the United Arab Emirates.
You have posted this question in several threads. Please take the time to go back to the threads you have posted to. You have been provided the answer, yet you insist on posting the question again. The answer is not going to change. You purchased the phone in Dubai. Facetime has been permanently disabled on that device. You will not be able to access FaceTime, and you will never get it. If you want FaceTime, you need to purchase a phone in a country that uses it, preferably in your own country.