Xbox live password reset no access to email linked to account

I am unable to reset my Microsoft account password due to a non-existent bellsouth.net password linked to it. The account was set up over 8 years ago when I set up my Xbox live account. I contacted AT&T(bellsouth) and confirmed this account has been deleted due to inactivity. My security question answer is not working either. I have completed the form with credit card billing info etc for my Xbox live account and the response I receive back is "email address from a provider other than Microsoft." And then prompted to have password reset sent to the bellsouth email which is not existent anymore.