AT&T email and Internet problem

[twinsdad]

Hi folks. This is my first post begging assistance. I just received an unlocked 3G that I bought on eBay. I put in my AT&T 3G SIM and the phone works fine. My problem starts with email and Internet. I entered my Yahoo name and password and it's telling me the password is invalid. I KNOW it's the correct password. I entered the same one on my old phone (Razor) and it works fine. I also can't connect to the Internet. I have a $10/mo. plan with AT&T but it keeps telling me that I don't subscribe to a data plan. Can anyone tell me what I'm doing wrong? Many thanks!

[JFSikora]

Call AT&T and tell them you just got an iPhone and that you need the proper data plan. Your current plan will simply not work.

[twinsdad]

Thanks. I was afraid of that but was still holding out hope.

[li2327]

You will definitely need the iPhone plan to get the full Internet benefits.