I purchased an unlocked, and jailbroken with redsn0w, iPhone 3GS off of ebay. I planned to use this with an att gophone. However, when I put the sim card from the gophone in the phone, it says no service. The sim works with other gophones, just not the iPhone. I have tried multiple sims, none have worked. What am I not doing correctly, because I've watched youtube videos doing the exact thing and being successful. Any suggestions? Thanks! By the way, it has the latest firmware, iOS 5.