It looks as if you have been using Simple Delivery for your items.
Your buyer needs to open a return stating that the item was damaged in transit.
Ebay will reimburse the buyer and you won't have to repay them or make a claim.
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)