I am under the impression (as regularly both an Ebay seller and buyer) that the responsibility is with the seller to get the item to you in the condition in which you purchased it. That assumes the seller has determined the delivery service, packed it adequately and securely and, maybe, taken out an appropriate level of 'cover' for the item should anything untoward happen (as it appears to have done).
Then ie now; (assuming the seller has not re-imbursed you already) you should, as I have done previously, submit an Ebay/Paypal claim for the purchase and 'shipping' costs ie a full refund.
Has discussion with the seller not taken place to reach such a conclusion?
I also assume that all correspondance with the seller, throughout the purchase process, has been via the Ebay 'system' - a very good safety net as I have also found (when a highly abusive buyer complained using the Ebay 'system' that, for purchase at 11am on Xmas eve of a very large item requiring unique packaging had not been sent that day. His words cost him a 'ban', his abusive feedback removed and all my costs in sellingcancelling it refunded.)
Paul.