Can't Unlock Phone

I have an AT&T phone that was bought from an AT&T store in March 2022 when I paid for it in full. From what I've read, my phone should be eligible for unlocking, which is what it says on the App. But whenever I try to unlock it, it says they aren't able to do so. I had another phone under the same plan that was able to be unlocked without issue. I've been calling customer support over the past couple of days (this started Thursday May 23) about this and (after a less than helpful representative referred me to Apple for some reason), I was told they would try to escalate my case and can see the ticket being in progress on the App. However, it says the estimated completion date is June 3. Between taking over a week for what should be a simple procedure coupled with the poor service with the aforementioned Apple referral, I don't have much faith in the system. I'd like know if there's some way get my situation solved quicker. I've read a few similar posts on here from people with a similar problem where filing a complaint with the BBB was recommended; when would it be appropriate for me to try that?

Also, one of the representatives I spoke to said this was an technical issue and their system was malfunctioning, but just for some cases. If that's the case, how common is this problem and if this is such a prevalent issue, why isn't more priority given to fixing it?

Since writing this, I tried unlocking my device again, but through the web portal. I received an e-mail saying I have a prepaid device (I do not) and I need to use the AT&T device unlock App on my phone (not on my phone, and when I tried downloading it, it didn't work). (Edited per community guidelines)