If he is contacting you through the eBay email forwarding system, forward vulgar or threatening emails to them as they will take steps to deal with it.
If he is sending these messages by email, send copies to abuse care of his ISP. They will also take steps to curtail his threats and vulgarity.
In the interim, if he is contacting you by regular email, block future emails from him. You are not required to tolerate morons who think the world revolves around them.
Good luck,
Bill
treasure-pot
Bill
