update: I just found (with some guy's notice) that iPhone I bought was actually a sprint model! dame it... I activated it with a sprint sim card. Was cheated... Sprint iPhone 5 is locked to AT&T and T-Mobile. But it is unlocked to international sim card. I am planning to use it abroad so not a big deal for me. Hope people be more careful when trading on craigslist. It's sad there is always some dishonest guy around.. Thanks for all guys replies. Sorry to take your time to answer my questions Hello folks, Today I bought a verizon iPhone5 on craigslist (because everyone apple store is oos..) The sim card is not with it. Now I cannot activate the iPhone. I tried to used an experied AT&T and T-Mobile sim card (I cut them), and a dummy verizon micro sim card from Apple store, but none of them work. It always says My question is how I can get my iPhone activated and use it with my AT&T sim card? I learned Verizon iPhone5 was factory unlocked. But I didn't expect the difficulty of activating it... Can I open an account from Verizon and have them activate this iPhone? I searched here and found people say Verizon can blacklist ESN of iPhone. If the seller failed to pay the contract, what would happen to my iPhone? Thanks a lot for anyone who helps!