Uh, those people do receive some kind of penalty. But the seller has to start the process.
If your buyer has not paid within 4 days of the end of the listing/auction, you the seller, on the 5th day, can cancel, citing "buyer did not pay" as the reason.
After you do that, here's what happens, fees are refunded and you are free to relist if you like and the buyer gets a "strike".
About that strike, when a buyer has two nonpayment strikes in 12 months, sellers can set their requirements so that they do not have to deal with that buyer. Have you done that?
BTW, when you mention a nonpaying bidder getting feedback, I had to stop and check the FB you had left because I was worried that you might have left negative FB for those buyers. No matter what the situation, a seller cannot give a buyer negative FB. Glad you knew that.
