If the item is marked Customer Damaged, there is nothing you can do. It is written in Amazons rules that they do not reimburse sellers for Customer Damaged items that are FBA. When you signed up for FBA, you agreed to let Amazon handle keeping track of your inventory, shipping, customer service, returns and returns pretty much anyway they want to do it.

If you FBM your items instead of FBA and a customer returns an item to you they damaged, you can charge the customer up to a 50% restocking fee.