The days of good person-to-person sale platforms appear to be over. The commercial market has vastly outgrown private sales so that's where the money is now and what all the players concentrate on. And the auction sites that still bother with P2P appear to have realized that feedback systems and punishing dishonest sellers reduce the amount of sales (no shit, sherlock) and this is their official excuse for reducing or castrating feedback. Basically, they are becoming scammer's paradise to increase their traffic and commissions. And if you don't like being scammed, remember that you can always buy from commercial sellers, at even higher price and higher commission to the auction site.
In Poland we have an old eBay clone called Allegro, which is doing everything to push private sales onto a separate sub-site that they started, where there is no feedback at all, by design. If you don't like what you receive, you can try their customer protection, which takes days of back-and-forth with the seller and their employees trying to work out what has happened and who is scamming whom, and if your evidence is convincing enough they will pressure the seller to make things right for you and occasionally refund you right away in cases of obvious scam. But as long as the seller cooperates and grudgingly accepts a return, they consider it a success and he can continue to list the same rubbish and look for new suckers who will consider the process too much waste of their time. Negative feedback? Forget it. "It discourages buyers, reduces sales, unduly punishes sellers, blah blah blah."
Even better is a classifieds site, OLX, which recently realized that there is more money in sales by mail than in person, so they try to promote themselves as such a site by offering escrow service. Looks fine until you read the fine print: they only cover sellers failing to deliver the item at all, if the item is damaged it's not their problem. They won't even tell you who it is that you are buying from. You go to the police, have them request the identity of the seller from OLX, then go after the asshole.
Fuck beancounters, man.