put an unpaid dispute in immediately.

don't waste anymore of your time on this buyer.

when you do this, you will have a choice to have an automatic closing of your case.

this gives the buyer 4 days to the second, and if they don't pay, ebay will close the case for you, any fees you have paid will be refunded to you, and then you can relist the item. 

don't forget to ban this buyer from bidding on your site.

....k