HBO Max subscription can't be verifed

I have Fiber 1000 and it included HBO Max. I've had it for about 3 years. I noticed that it was $10 cheaper, so I called ATT to get the discounted price. The customer specialist said that she's having computer issues and could not get me that discount. I said that I could downgrade and try to see if that met my needs, but I WAS NOT told that I would lose HBO Max. When I realized that I lost HBO that same day, I went online and upgraded my account back to my original. The problem was HBO is no longer being offered with the 1000 plan. I call customer service to see if it could be added, and they said they're going to escalate it to see if they can add it back to my account since I was "grandfathered" in. I received an email from ATT on 7/28 (case ID 84474344)  saying that they added HBO back to my account. Great, the only problem is every time I try to login with 'HBO > Sign In With a Provider > ATT Login' I get a "Can't verify my subscription" error. I spent easily over 6 hours talking to various people; customer service, support, managers, etc. on various days and none of them can figure this out. I also spoke with HBO a few times and they want me to contact ATT. Today I was on the phone for over 2 hours, not on hold, but actually talking with people. The first person was a support specialist, and I was troubleshooting with him and then he was on hold for 40 minutes waiting for the backend to get back to him. When they finally did they said it was an activation problem. He transfered me to another department. Then I was speaking with them for quite a while, only to get transfered to another person in which I finally had enough and wanted to talk to a supervisor. When I did speak with a supervious, all they could do is esclate it. What a joke. At this point I'm considering looking for other internet providers.