This is an AT&T iPhone 5. I have confirmation email from AT&T confirmed the phone is unlocked. I follow the instructions in the email to unlock, connect to iTunes and run Restore. When it's completed, I don't see the "Congratulation your iPhone is unlocked" message. When insert a T-Mobile SIM, it tells me Invalid SIM. I rechecked unlock status page from AT&T and it still says the iPhone is unlocked. I called AT&T tech support and they also tell me it's unlocked. I tried to call Apple but they tell me I have to pay $20 before they even take the call. What should I do?