buyer sent back destroyed item and got full refund from amazon

Hi, i got a message from a buyer who said there product was not working and it did not fit, so long story short buyer bought the wrong size, although size was indicated in title and product description. he blamed my product for not working, and said his dog chewed it up and he was sending it back, amazon knows its chewed but told him to send it back like that and they sent refund once it shows it was sent back. now im stuck, i dont want a complaint or negative review but i also dont want to pay for buyer to destroy item and eat the cost. what can i do?