Phone locked and unlock request "In Progress" for a week

I bought a new phone ~2 or 3 years ago from samsung.com directly paid in full.  It was a AT&T Unlocked  S8+.  I never used it on AT&T, I bought it to use on Straight talk.  It worked no problem until a week ago when I switched phone to another mvno Mint Mobile.  My phone is apparently "locked" and it wont read the new Mint mobile T-mobile Sim card and wants an unlock code.  Don't know why my unlocked phone is "locked" but Samsung was no help.

So, whatever, I buy an unlock code on ebay to unlock it.  Unlock code seller can't unlock it, the EMEI is tied to an AT&T account and frozen to it.  I never had an AT&T account or service unless I somehow made an account when I set up my phone?   So I don't see how it can be tied to an AT&T account.

Ok, so next step I try to unlock it from AT&Ts website for submitting an unlock request.  It submits and tells me the unlock is in progress and can take up to 2 business days.  It has been a full week now and it still says the same thing and that it is in progress.

The only customer support I can find is the one number listed on the website here.  I talked to customer support for 30 minutes and they had no clue what to do and kept transferring me back and forth and told me to use the website.  So now I'm at a loss as to how I can get my phone unlocked from a carrier I never used.