Helen:
Elgato raises a good point - if you need the email account that is attached/related to the auction account, you might want to just let it go dormant!
If you don't and truly need to close it, the best way I've gotten support at Yahoo (auctions) is to use the feedback button, right side of the page - closer to the top (in a box area), and share what I need/where I am having an issue.
Hope this helps you!!
