Here is all the information I pulled for you that you should need to unlock. Good Luck!
Unlock your device
When referring to unlocking a device, there are three specific types of unlocks that are separate and unique:
Carrier unlock: To unlock your AT&T device to work on another carrier's network, submit a device unlock request. You can also submit this request if you want to travel internationally with another carrier's SIM in your device.
Device screen unlock: You can require a PIN, password, or pattern to unlock your device screen to protect your device against unauthorized use.
SIM unlock: For additional security beyond a screen lock, you can require a PIN code to prevent your SIM from being used in any device without entering the PIN code. If your PIN code is entered incorrectly more than three times, your device will request a PUK code (PIN Unlock Key) in order to unlock the SIM.
Once you've determined the type of unlock you need, view the instructions below for your specific need.
You can submit a request online to unlock your device to work on another carrier's network. Simply visit us at Device Unlock to review the requirements and then submit an AT&T Mobile Device Unlock request. Requests may be completed within 48 hours, but may take as long as five business days.
Forgot PIN or password to unlock your device screen
If you have forgotten your screen unlock PIN or password, use our Troubleshoot & Resolve tool for instructions for your specific device.
Forgot pattern to unlock your device
If you forget your screen unlock pattern, you will need to a pattern reset to unlock your screen. Use ourTroubleshoot & Resolve tool to get device-specific instructions for performing a pattern reset.
Unlock SIM or PUK
SIM Lock PIN code
When enabling SIM Lock on your device, your device will prompt you to enter the PIN:
The default PIN for an AT&T SIM card is 1111. For additional security, you can change this PIN code.
When you enable SIM Lock, the security option follows the SIM card if the card is moved from one device to another.
For instructions to enable SIM Lock, consult your device's User Manual. To download a copy, visit the Device How-To center and select User Guide.
If the SIM Unlock PIN code is entered incorrectly three times, the SIM card will lock, and you will need to get a PUK (PIN Unlock Key) code from to unlock your SIM card.
You can get the PUK code online by following these steps:
Select myAT&T at the top of the page. If prompted, log in. Don't have a myAT&T login? Register today.
At the top of the page, hover over Wireless Services, and then select My Phone / Device.
If necessary, click Select and choose the mobile number that needs the PUK code.
Under Manage my phone/device, select the Unlock SIM card using PIN Unlock link.
On the Unlock SIM Card Using PIN Unlock Key screen, view your PUK code and follow the instructions for unlocking your SIM Card.