You can open non payer disputes 4 days after the sale ends and anther 4 or 5 days later close the dipsutes.

This will give the buyers non paying strikes and get you your FVF refunded.

Have you got in place the blocks to stop 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.