Since ebay have stopped sellers from leaving negative feedback, the number of non payers have just increased as we can't do anything about it

Do you have evidence of this? I am not saying the number of non payers has not increased but as a percentage of total sales across ebay I suspect the percentage may be less. I certainly have a lower percentage of my sales unpaid than I had over six years ago. The number has stayed about the same but6 I am selling at least three times more than I was selling when you could give negs.

I rarely gave them to buyers anyway as it usually resulted in a retaliatory neg which does nothing to stop a buyer from buying but is not a good look on a seller's account.