Unmerge Yahoo account from AT&T

Is there any help for unmerging a Yahoo account?  I am guessing this should have happened automatically but I cannot log into Yahoo and when I try to login via att.net it says the account is locked.  The tech at Yahoo I spoke with said the problem is that AT&T needs to unmerge my account but the last few AT&T techs I spoke with say they have no access to the Yahoo accounts anymore.

Stuck in limbo...