Buyer did not pay.

I tried to cancel order but it is too late.

What do I do? 

There is no option to lodge a complaint. 

EBay is going to charge me a percentage of the sale. 

If I just relist the item what happens if the buyer appears and complains?

I sent reminders. I could not send an invoice, the instructions for that took me nowhere. 

How do I lodge a complaint with EBay regarding this buyer?