unlock issue

Have the original owner unlock it.  Usually it takes a few days after the final payment for it to be registered on the unlocking site, or the final bill may have to be settled if the account was closed.  You may simply have to wait a while longer, but still the best option is to have the persons who sold it to you unlock it.  Let them deal with AT&T, and if there’s an issue, they are much more likely to get it resolved since they have, or had, an AT&T account.

Are you the original owner and if you are how long ago did you pay it off? 

Am not, the original owner showed me the proof of payment before I paid for it.

The contract started in Aug 2019 and was paid off last week.

I can make you a fake receipt. Unfortunately at this point if it shows unpaid only the person you got it from can clear it 

It's not fake am 100% sure.

okay, thanks

When it comes to Device Unlock, @olalekanbabs, there are a couple of things to keep in mind.

First, we want to advise that @dwill05 is correct. As stated at AT&T Device Unlock Help - Solutions & FAQS, under the section eBay & Non-AT&T Purchases, you'll find these details:

If a phone is purchased from a non-AT&T authorized dealer or sites like eBay, AT&T may be unable to unlock the device. Before purchasing the device, make sure the seller performs the unlock request. In some instances, you will have to contact the seller to perform the request. If the device was purchased by another provider, they should have online resources to unlock the device.

There are other important information on that same thread including General Requirements for All Unlock Requests:

We hope this information helps. Thank you for contacting AT&T Community Forums.

Lar, AT&T Community Specialist