I used to be on an account with my ex under her mother's name. We broke up, I got my own account. Magically my email address, and most recently my mailing address, got added to her account which was never on there before.
I get all her bills and every detail about the account!!
I've contacted AT&T about this twice and was told there was nothing they could do.
I'm going to start posting the bills publicly until something is done about it.