Awesome Sean! Was hoping to find an active at&t customer on meta, can you update here with the progress down the at&t escalation rabbit hole?
The key here when you are discussing this with them it to get this escalated to level 2 and level 3 support, at the lower rungs of support it is very unlikely you will get any traction. Essentially just insist that you paid for working Internet and got broken Internet, can you escalate to your manager?
If you share responses you get we are happy to guide you.