All buyer will have 100% feedback as they can not have anything less unless they also sell and have got a neg feedback.

Sellers can not leave negs for buyers hence the 100% for all buyers.

All you can do is open the non payer dispute after 4 days and close it 4 days later and add them to your BBL and put the blocks in place for the non payers.

To put these blocks in place hover your mouse over account in your my eBay page and from the drop down click on Site Preferences then go down the list till you see Buyer requirements and to the right of that click on show then click on edit. From there you can put in place the blocks you want, to stop those you want to block from purchasing from you