Can not access yahoo mail

Hello, I changed phones this past summer and then was unable to access my email account. I was asked 2 questions to validate. #1. an alternate phone # that I no longer had access to (turned off). #2. alternate email with att that hasn't been used in like 15 years. I believe my password is correct but perhaps my account was hacked. I since opened another yahoo email account but I would really like to get back in to old account. I had it for many many years and I have alot of files. Thanks for any advice you may have. Cindy