I can't unlock my device.

Allow us to share the guided steps on how to unlock a device purchased from a third party @Hercullesviana.

We appreciate the support both @sandblaster and @lizdance40 has shared as they are correct.

All devices requesting to be unlocked will be requested using our device unlock portal. First, you'll want to confirm that your device meets all personal device requirements. If your device doesn't meets all necessary requirements, you'll be notified for the reason being. If this happens to be the case, make sure that your device has been cleared of all requirements and resubmit your device unlock request.

When experiencing technical errors while submitting your request, you can reach out to us and we'll further assist with unlocking your device. If your device was purchased through a third party. It'll be best to reach out to the original owner and have them reach out to us so we can access their old account for review and run a eligibility check. Then if able, we'll go ahead and unlock the device. Otherwise they'll need to clear any linked account requirements before the request can be approved.   

We hope you find this information helpful.

Thank you for reaching out to the AT&T Community Forums Team.

Jonye, AT&T Community Specialist

If you purchase a second hand phone, only the original owner can remove it from their account.    

The first owner is saying it's already unlocked, but it isn't. Is there anything I can do?

What procedure does the owner have to do? Can you tell me?

That all depends on what “linked to another account” actually means. Typically all they need to do is use a different phone on whatever line the 8 was being used on. However, if there is some other account issue like an outstanding debt, that would need to be cleared up.

For the owner to unlock, is it via the website or by calling?

All unlocks are done through the website.

@ATTHelp how can I contact you to request unlocking? the former owner insists that he has already unlinked his cell phone from his account 

@Hercullesviana

ATTHelp how can I contact you to request unlocking?

You use the portal... 

https://www.att.com/deviceunlock/

The Portal informs that the device is linked to an account, but the former owner insists that it is not.