I can confirm the same thing happened to me.
In my case I know what I did wrong: I was outspoken about abuse at Yahoo! Answers. I even posted here at YDN about not being allowed to mention the Answers API at the Answers Suggestion Board. Although the Yahoo! Widget and Answers Badge have the same functionality as the API, I was forbidden by the Community Manager to mention it.
I also posted there about privacy abuse since the Community Manager has decided to frequent an off-site chat (Chatzy) where information about surfing habits and login IDs is being shared with regular users ( see Answers Suggestion Board
http://suggestions.yahoo.com/detail/?prop=...&fid=173584 ). I also filed a privacy complaint because my registered first name was revealed.
She deactivated all my accounts (this is a new one) and there is no appeal process. Yahoo! telephone support was useless. I use many Yahoo! services such as Messenger, Mail, Groups, Avatars, Profiles etc. All are gone and I can't even get to those suggestion boards.
In my case I offered realistic advice at the Suggestion Board and was banned for it, but I've seen many (who complained at the suggestion board) who have been deleted without notice and without appeal. The system of allowing users to moderate other users at Answers is to blame. No single property should have the power to ban a user from all services without appeal. No single community manager (however charming) should be able to ignore internal guidelines and privacy policies.