Desperate to be able to log in to my Bellsouth email

This is the third of fourth time I've posted a question with the same problem.  I cannot log in to my bellsouth/yahoo email on my desktop. 

This email is my business contact and I need the problem to be resolved.  I have done ALL of the suggestions received from AT&T. Can't get in to att.com/myatt or any other "help" source. Can I please get some direct contact?