回复：ebay上遇到刁民怎么办

I'm a Ebay costomer only, but I think you need to do:

collect all your communications with this ID . ask some one who can talk clear to tell ebay the whole story indicating the relative evidence. ebay and paypal will help you to cancel the transaction.

to prevent him to blackmail you later using another ID, you may send him a gift for inconvinience.