Ask HN: What to do when beholden to AT&T's flawed sign-in state machine?

AT&T is the only internet provider in my area and I needed to sign up for service with them. They seem to have magically linked my account to my parent's account and I am stuck in an endless sign-in loop. They have snail-mailed me codes that I've had to wait for, they have called my phone with an automated system and sent my my plaintext password that I generated with 1password via email. I am fed up. Has anybody else experienced this awful experience with AT&T's account management system? It seems like they have 5 different systems that are all patched together. Would love to hear from an engineer that actually works at AT&T as to how these systems are so bad.