Confused
You did not mention if the iPhone was registered under your name or your girlfriends name on your previous family plan account, nor how long you were in that account, or if you were listed jointly. When you & your girlfriend first opened the iPhone account, I suspect you had a minimum contract term, and a penalty if you terminated the account before the end of the term. I am sure AT&T would establish an account for you (providing you were credit worthy, etc.), unless there was something wrong with your previous account. To me, this would be no different then a divorce or dissolution of a domestic partner relationship, which I expect AT&T to have a procedure for. Obviously, I do not know enough to guess why AT&T would not set up an account for you. In my opinion, if you want to take full advantage of the iPhone and it's features, then AT&T is the carrier for the iPhone in the US, and can provide those features. If not, unless you are very techie, getting the phone to work on another carrier's compatible network is a real challenge. Depending on the region and assuming an iPhone 2G, I suspect it would cost you about $60 a month (plus tax & misc fed fees, etc.) for a nationwide calling plan with 450 anytime, 5000 nights & weekends, and unlimited data with 200 text messages. You can check this out for yourself on the att.com website, or visit a store. Good luck!