He will have to return the camera at his expense, by trackable means, in order to get a refund from Paypal. He will also, I believe, have to tell Paypal how the camera was not as described. Which you can dispute, once he returns it.

Wait. A lot of threats are exactly that and if he can't provide proof, he should lose. You might have to twist Paypal's arm, but there are plenty of members who can advise you on that.