Charging me shipping for a large item return i have refunded

So i sold a large item that was expensive to ship that the buyer payed for UPS Completely destroyed it i paid extra to insure it through the ship whatever coverage and i refunded them when they asked for a return but i dont want and dont have room to accept this large item back. It had been closed and now all of a sudden weeks later i get a negative on my account of hundreds of dollars the person somehow is sending me this behemoth back and now they are charging me for shipping? Please why do i fucking do i am about to have a heart attack i can hardly type on here idk where or what to atart becausw i cant get support on the line to explain idk how to start a damage report with whom there is nowhere no protection