He should refund ALL your money including return shipping, If he isn't willing to do that I would leave him a negative feedback, It was not any of your fault he did a lousy packing job and was too cheap to put it in a secure box. He at least owes you a partial refund for the damage if you decide to keep it. Sellers cannot leave buyers negative feedback any longer, only positive or none at all once you pay them. Be sure to mention his poor packing job in your feedback. That's how we can tell good Ebay sellers from poor ones. Ebay has cracked down on sellers tricks like makeing the buyer pay for return shipping and leaving negative feedback to buyers who pay on time.
No good deed goes unpunished.
A loaded gun, a faithful dog,,, consider yourself lucky.