Seller wants to return item that was dented by USPS.

[kdola321]

I sold an item that was brand new (insulated water bottle) and during the transit period the bottle was either dropped or mishandled by the post office and when it arrived to the buyer it has a huge dent in the corner. I have listed that I don’t accept returns but the buyer wants a full refund and return. Do I have any options that protect me or do I lose out either way? So I lose money and get a returned damaged bottle?