You did the right thing...you nailed them.
If you're tossing it back and forth..think upon it this way..
You saved your fellow eBay sellers from having to deal with a perpetual nonpaying bidder.
When I deal with the situation that's just like yours...I do not EVER clear an item up after I NPB them due to the reason I gave above.
My thoughts? If they'd sincerely wanted to keep their ebay account, they wouldn't have gotten to the point where my third strike against their account would have happened. (or second strike)
Go with your gut feeling and just flat out ignore them. What they did to you, they'll eventually do to another seller.