Given you only created this account in 2013, unless you have used an older account in the past, you would never have been able to give a buyer negative feedback as they removed that option 5 or 6 years ago. In view of that, I'm not sure how you could say your non payer issue has increased since you can no longer leave negatives for buyers with an 18 month old account?

Do you have blocks in place to stop the serial pests? Why would you want the ability to leave a buyer a negative when they will turn around and give you one straight back? A buyer could have lots of negs and still buy. You get so many and they shut you down for good.