This spring, I bought a used iPhone 4s from a phone dealer. He told me it was a Sprint phone, but it was jailbroken and gevey sim unlocked to work on the T-Mobile network. He said it was $100 cheaper than a fully-unlocked phone because Sprint does not unlock phones, but he assured me it was legal. Maybe it was legal, but it doesn't work that great. I can't send/receive MMS messages and I can't update my IOS. I'd like to just the get the thing fully unlocked. Is that possible? I'm hearing that a law was passed requiring the carriers to unlock out of contract phones. Is that true? And if I'm not a Sprint customer, can I make them unlock a second-hand phone? Would the phone even work on the T-Mobile network? Thanks for your advice - I just really don't know anything about how this all works.