Welcome Im Cory
http://us.mc598.mail.yahoo.com/mc/welcome to go back to Yahoo Classic Mail.
See if you are able to access your mail.
If this works please right click the link and add it to your favorites or press ctrl+d to bookmark it.
You will need to use it everytime you use mail because you can not go back to Classic Mail Permanently.
Let me know if you have any questions.