This is not a new kind of story on eBay but I'm not sure what the answer is. The reputation system works to some degree if someone commits systematic fraud but if someone does this as a one-off thing, I'm not sure what reasonable protections are other than using some sort of escrow service.
You can argue whether eBay's policies should default to favoring the buyer or the seller but they pretty much have to do one or the other. Even if their customer service were better than it is, it's not in the position to do a forensic investigation in cases where the facts are in dispute and can't be easily determined.
No, one or two minutes spent by a human would easily resolve this situation and most disputes. Just taking a look at the images and serial numbers of the macs would provide the evidence needed. Ebay does not have to be the shitty company it is. It chooses to be the shitty company it is.
Maybe the seller could've recorded as many serial numbers of parts of the Mac as possible? Ive not bought or sold stuff on eBay in years so I don't know if this would've helped.
You can argue whether eBay's policies should default to favoring the buyer or the seller but they pretty much have to do one or the other. Even if their customer service were better than it is, it's not in the position to do a forensic investigation in cases where the facts are in dispute and can't be easily determined.