On darknet markets they use an escrow account and admins act as mediators, so as long as you can show that you have a valid tracking number. The issue becomes when people try to scam you by selling you broken electronics or scam buyers pulling fraud returns. Weirdly this is common with VCRs on eBay. There’s large resellers who buy good VCRs and steal parts out of them and return them. Then they resell on Amazon. I guess it comes back to having a karma system.