A couple other things to consider:

As noted in an earlier post, you can leave a "positive" feedback that includes a negative report - but eBay can also refuse it or overturn it.

I would consider excluding that bidder from future auctions to avoid retaliation

I would also consider setting a buyer qualification in your seller preferences: if someone has any non-payment issues in the past ("buyer strikes"), you can exclude them from bidding in your auctions. There are other options for exclusion, too, such as buyers who don't yet have a certain level of feedback.