I have a new 3G

Question

I have a new 3G I phone 16g. I have tried & tried to get it to sync to itunes. A pink screen comes up to register it.I accept the terms and save. It shows my phone in the devices but I can't sync. I was able to drag and drop my music into it, but that is all. I have the latest version of itunes. It syncs with my Itouch and my other ipod. So I don't think it is my sofeware. I think it is the phone. ATT&T did nothing for me other than give me a phone number to call. On hold for almost one hour. I gave up. HELP! HELP! HELP!