Well, first off, you should post all the details about it here
http://www.chargebackforum.com/consumer-fraud/ so at least others can be aware of him. Then let him know that you have reported him to Chargeback Forum, that's bound to get some attention by email.
In regards to PayPal, their seller protection policy doesn't cover services so the best you can do is show him you did what the job entailed.