Couple months ago,I was updating my email address they have for me and the site would not allow your UserID (Member since 1999) to be the same as your email address.
Ebay name - jamesxnj
Email - jamesxnj@ (has changed quite a bit over the past 12 years).com
Had to change it to my Yahoo mail addy.

And it works better for me,cause ebay spams daily it seems.