Reset password for sbcglobal.net email account, no longer have ATT account
I have had a sbcglobal.net email account for almost 10 years and used the same password until recently. Due to the Yahool data breach, I changed the password but now need to reset it, since I forgot it. Fortunately for now, I can still access the account on one of my devices. When I try to reset it online, Yahoo directs me to verify my ATT account info. I no longer have an active ATT account and disconnected my service in 2015 when I moved. Since resetting it online does not work, I have tried to contact the ATT digital help line several times and have had no help.. Finally on the last call, they ask me to verify my ATT account number and a phone number. After reaching back into my memory, I could give them an old home phone number which the customer service rep confirmed, but I could not give them an account number. They told me the only other option is to go to an ATT store with two forms of ID and they could reset it there. I am working overseas at the moment and there are no ATT stores over here. What else can I do to have this password reset? I can provide a lot of other informaton to verify my identity, but need someone to work with me.