If you have no problem in the past, there should be something change that makes you are unable to cash out now. Since the message is about a problem of your phone number, are you sure there is no problem with your number? I mean it may be no longer active or something else. By the way, you just need to wait for now if you have reported the case to the team. I am sure they will respond it soon. 

If the problem is about the country of the user. He must be unable to cashout since the early of joining BC.Game. In fact, he has no problem to cashout in the past.