Hi auntbetty.. Your buyer has won 13 items since joining.
Sent a reminder today , perhaps give a couple of days but then with no response or payment , file the unpaid dispute to recover your final value fee. Here is process..
http://pages.ebay.ca/help/sell/unpaid-items.html
Buyer has 4 days to pay. Does not , close the case and ebay will credit fee and assign a strike to buyer's account.
Add ID to your blocked bidder list..
http://pages.ebay.ca/help/sell/manage_bidders_ov.html
Do you have buyer requirements set to block buyers with 2+ strikes.