Email password resets (or account recovery) for non-customer

I'm trying to recover two old email accounts with .snet domains.  I used to be an ATT customer, but when phone operations in Connecticut transferred to Frontier I was forced to leave ATT.  I can no longer access these two email accounts, but I believe they still exist.  Frontier says they can't help me, and ATT won't help me because I'm no longer a customer.  I'm willing to pay ATT to get these accounts recovered, but I can't figure out how it could be done.

Any help you could provide would be appreciated.