Accelerator error

Hi, my dad has an sbc global email account that he cannot currently access. He has spent many hours on the phone with different people at AT&T trying to resolve. He has changed password, tried to set up security key, etc etc. he can login with his credentials on the currently site, but still can’t access any mail. At one point there was error saying he had overdue bill which was not valid. It is to the point of being absolutely ridiculous- none of the steps are working and he needs his emails. We need to speak with someone that can actually fix the issue vs sending us through hours of phone calls and multiple steps that do not work.