I’m so pissed off

I just started to build computers for a profit, I sell them on Jawa, eBay, and marketplace. I put them back in the same packaging the case came in. When I got my very first order on Jawa this guy bought it, made a new account, and messaged me that he bought it. Lil sketchy but It was okay for then. Then when it got to him he said the cpu doesn’t work. And he said he “swapped out the gpu and cpu” then he said later in the convo he didn’t, so I was sus. He sent it back to me in this condition, what do you think I should do?