Can't get into e-mail account.

When I try to log into e-mail, My e-mail account number shows up. I get a notice that no account shows in Yahoo. Then asked if you could send code # to my phone. Unfortunately my phone number has changed. Help please........I cannot get a response from you via e-mail as you request.....I can't get into it.. (my problem e-mail address is ***@***) Thank you in advance for you help with this problem.