I am interested in changing carriers on an existing Iphone 5S. Should I request the unlock when I already have service lined up with the new carrier? I requested that AT&T unlock the phone and they did immediately. Now I have no service whatsoever -- can't even make a phone call. I had no idea that was going to happen. I am not sure if I should cancel the request (I have 24 hours to cancel it). Can I re-request it?