Contact the buyer one more time, apologise for the damage, and ask them to open a Not As Described case for return (or refund without the need for return if you prefer). Send them a link to the Money Back Guarantee as some buyers (bizarrely!) have no idea of its existence. Ask for photos of the damage so that you can lodge a claim with the carrier (or Packlink if you bought the postage on Ebay).
Once you've made your buyer whole, he may be happy to change his feedback. If so, send him a feedback revision request so that he can do so.
But if that gets you nowhere, and Ebay won't remove the feedback (I see nothing in it which makes it removeable), add the buyer's Ebay ID to your Blocked Bidders List, and add a response to the feedback. Remember that your response is for prospective buyers, not for this one. Negative feedback in itself doesn't put most prospective buyers off - it's how a seller responds that might. So keep it calm, factual, and professional.
@georgeandmikdred
