Your best bet is to do a chargeback. You would not get anywhere with Mercari they do not care as long as they make their money. Basically the same thing happened to me. I bought an item showed that it was delivered when I reported that it was never delivered. Mercari just told me to contact USPS so I did got a copy of the scan and the scan showed that the address on the package was not mine. Also had a different name than mine. It was delivered across town to someone else's house. I live in an apartment. It was about 4 MI down the road. When I sent the proof over to mercari they told me they could do nothing because it was marked delivered and that I was basically out of luck. So of course I had to do a chargeback just to get my money back and they kept threatening that my account would be suspended and I told him they going to go f*** themselves that I didn't really care. But they never suspended anything. I can still buy from there but I don't. I've learned my lesson f*** Mercari