All, I know this question is asked many, many times here, but I truly need some help. I bought a used iPhone 4 off of Craigslist. When I took the phone into AT&T to get it activated we ran into an issue. They connected it to iTunes and it says, "The sim card in this phone does not appear to be supported." So the AT&T rep said it is likely a foreign phone and to go to Best Buy and purchase an O2 universal sim card and that should at least get it past the activation. The only option he said was to see if I can get it past the activation and then wait for the next jailbreak/unlock to come out for the latest software and then unlock it to use on AT&T. So I bought the O2 universal sim and when I trimmed it and installed it- I get the same message again. Needless to say- I feel like a complete ass for not doing a better job buying this phone. What can I do- what are my options? How do I even find out what carrier it is connected to so that I might buy a sim card from them and try that? Even if I can't use it as a phone, all I want to do is at least use it as an iPod. I know I did something stupid and I have tried getting in touch with the seller to no avail. I feel pretty helpless. Any and all help/advice is GREATLY appreciated.