Your bidder sounds like a serial nuisance. Very annoying.

Putting a warning here or anywhere else won't do much to help other sellers but you can help yourself, by doing as countessa suggested.

First set up your blocks so buyers with a couple of strikes against them can't bid on your items.

Make sure you put this particular bidder in your blocked list too.

And make absolutely sure you don't just cancel the sale, that instead, you put in an unpaid item claim for every unpaid item. That will give your bidder some strikes. That will be the greatest help you can give other sellers, plus it ensures you'll at least get your selling fees back off ebay.

Giving a strike to a non paying buyer is the best way for you to get some revenge because there will be quite a few sellers out there with blocks on people with strikes and when your nuisance bidder tries to buy from them, they'll get a message to say they can't buy. That will put a spoke in their wheel. I know you won't be able to see it when it happens but believe me, it will upset that bidder a lot more than your effort giving positive feedback & a bad comment. All you did was push up their score, make them look better. Hit them where it hurts with a non paying bidder strike.