Don't send it back until you've been refunded. Make the paypal claim saying 'not as described' dont mention damage in transit the buyer can do that its not down to you. Then when you get refunded send it back to PAYPALS HEADQUARTERS tracked and insured. The buyer will have to pay to get it sent back to him from paypal and will go some way to teach him not to be a lying scrotum sack in the first place.