Charge back. Most of the time, you'll win. If you want to take it a step further, call his parents and tell them the situation, this way they're aware and teach him to not do anything alike. Just charge back and put it behind after learning from your mistake.
You can chargeback from paypal ,thats what i heard from some friends not sure if its true but its easy (when i google it every1 say its easy to chargeback)
Just submit a chargeback claim through paypal against his address, provide as MUCH information as you can regarding the incident. 99% Chance you will win. THEN AFTER, call his parents and tell them how much of a little cunt rag, waste of semen he was and then give somebody his IP who knows how to ddoss and fuck up his internet.
Chargeback,and since he was a little,lying prick about it and you have all that information about him. Get creative