Help to delink/unmerge ATT address from Yahoo

I've had a Yahoo email account for 20+ years. Many years ago I had sbcglobal as an internet service provider. At that time I linked my Yahoo account with sbcglobal.net. Now that ATT owns sbcglobal, whenever I log into Yahoo, it diverts me to the AT&T login screen. I do not have an ATT email address (other than the one I used to create this account to login here). Can I get some kind of reply please without deleting my message?