Please Help! No Access to Alternate Email for Verification Code!

Hello,

I am trying to access my yahoo account on several different devices (iPhone, iPad, and Macbook), and each time receive a message that I must verify that it is me trying to access my account by entering a verification code that is sent to an alternate email. There are no other options given. Problem is, I no longer have access to the alternate email on file as it is my old college email from 13 years ago. The Yahoo help page has been no help. What can I do to gain access to my account???!!!