unlock

Does the phone meet all the requirements?

I'm not sure. I will be given to buy it on ebay. I don't know how to check if the contract has been canceled. imei I know

Get a refund

I have not purchased yet. I want to check before buying if the seller is cheating. Is it impossible to find out by imei if you can unlock the phone or the contract has not been paid yet?

theres no way to find out, at&t will not share account information

You would need to request the seller provide the IMEI and then make then check the unlock portal (as a non-customer). 

Ebay has fairly decent customer protections. If the phone if being sold as unlocked or unlockable, keep a copy of that advertisement so you have evidence for a refund if necessary. 

Yes. I want to do this, but the site always gives "Oops! Looks like we're having network difficulties. Try again later."

I am not a resident of the USA. Therefore, I will have problems if the seller has not closed the contract with At & t.

Excuse me. Maybe someone will check the possibility of unlocking by IMEI. I wrote to support, they replied that they do not provide support via email now (use myAT & T). But I am not an att user and I have no att in my country. It turns out silly. The contract is paid, the IMEI is not blacklist, but I cannot unlock it, because I am not on the At & t network.

Find a different phone you have been told over and over again you can’t unlock it. No one here can check anything. This is a customer populated forum not AT&T. Again you can’t unlock it