Hi, I have a iphone 4 AT & T as I am in mexico and is out of contract and want to put a microchip telcel.
Assuming you were a customer with ATT or paid full price from and authorized seller, you can call ATT at the number below and they will determine if you are eligible to have your iPhone unlocked. See the phone number below. You can use Skype to make the call to keep your international calling costs down.
For service or support questions including existing order status, call: Customer Support: 1-800-331-0500
Information on iPhone unlocking can be found here by copying this link into your browser: https://www.att.com/deviceunlock/client/en_US/