Go here
http://resolutioncentre.ebay.ca/
and start an Item Not Received dispute.
If he does not refund you voluntarily (do NOT agree to a 'replacement', it won't arrive either) then Paypal will and go after him for their money.
He will have a black mark on his selling account.
If more than 30 days have passed, act immediately. You have only 45 days to complain.
You can leave appropriate feedback for 60 days. At that time you will be asked to leave Detailed Seller Ratings. A normal transaction gets Five Stars . The lowest rating is ONE Star. No stars is a free pass.
If more than 45 days have passed ask for further advice.