I have worked for At&t as a rep before, so I have little bit of knowledge on it. If you do as what sexi in sary said then T mobile will send bill to collection agency if you don't pay which will hurt ur credit score. For At&t as a customer service in this type of situation we used to give credit and block international call so it won't happen again as a. Phone company's people knows this kind of situation happens to some peoples. If rep refuses to take it off, ask for supervisor and talk to supervisor. If you bad luck is not so bad then you will get nice supervisor. then save $$$$$$