sbcglobal.net email receiving "Not found on accelerator"

I've jumped through all the hoops regarding the email and the errors talked to dozens of people in various call centers and at this time AT&T does not believe it is an at&t issue but a yahoo issue.  It supposedly has been escalated to the yahoo team for resolution. At this point it is very difficult for me to believe anything I hear because all solutions have had one thing in common "Wait 24 to 48 hours" and I've waited and still no working email.

This whole issue started when my DSL was as good as useless and that remained that way with nobody being able to resolve the problem. Fortunately our local cable provider was offering a bundle service of phone, internet and TV so I took them up on it just so I could have decent Internet service.  I cancelled all services, other than my cell phone, with AT&T, which included internet, Directv and landline phone. That has been three weeks now and I still do not have email.  You know that this is the truth because who coul;d make this type of stuff up?