Lumia 1020 Unlock Problems

I bought an AT&T Nokia Lumia 1020 off of eBay to use for other carrier

Description said it was unlocked, inserted SIM and found out it's not, it's locked to AT&T

I go to the unlock site provided by AT&T and enter the IMEI as a non-customer

Site tells me "The IMEI you entered does not appear to be an AT&T wireless phone or tablet" which I know is a lie because THE AT&T LOGO IS ENGRAVED INTO THE FRONT OF THE PHONE

I re-enter my IMEI several times to make sure I have it right, to no avail

So I hop on over to this other AT&T IMEI checker provided by AT&T and copy/paste the EXACT number from the unlock site into this new site

It recognizes the device info correctly, tells me the phone is perfectly compatible and that everything is peachy and they'll sell me a plan as soon as I want one.

One of them is lying.

I'd rather not use this phone for AT&T, so can anyone tell me how to go about unlocking it? (Yes I know there are third party sites to do this, and they're all shady, extortionate, and outdated. I'm trying to keep it above board)

tl;dr: Either AT&T system is broken or intentionally lying, need Lumia 1020 unlocked, avoiding third party sites

Are there any passing AT&T reps that can give me a hand here?