I received my unlock code from at&t and followed the directions but after the device turns on with the foreign sim nothing happens.... There is no dialog asking for the NCK... I've tried a good deal of the dialer codes for LG but none of them bring up the prompt... Is there any way at all to do this

I want to check that my GoPhone account is successfully canceled and know how to unlock the device as a non-customer. I need to activate my phone in my country now but I cant because the device is still locked. The number that I used has already expired and someone uses it now, so I couldn't unlock

I cannnot unlock my device as a non-customer because mine is currently active on another AT&T customer’s account. Is there any another way to unlock my device?