This is an interesting thread.
I see the argument for just letting it go, as I've done this many times with little issues and it just wasn't worth the hassle. I also understand the buyer frustration, because I've been in this situation and ordered games before only to receive counterfeit copies. I'm a lot more vigilant now than I was years ago, and so I haven't been defrauded from ebay in a while, but it has happened to me many times in the past.
I can specifically remember one case where I ordered something from Italy (it was about $80 including shipping), and the estimated shipping time was around 3 weeks. I contacted them about 4 weeks later, and they said there was an error and they would reship - after about 2 weeks I contacted them and got no reply. A week or two later they no longer had an ebay account. Nothing I tried with Paypal or ebay worked in getting a refund because the time that had elapsed was too long, according to them. So I was out $80. This is just one of many cases where I've been screwed before on ebay.
In another case, my iTunes account was charged $100 for gift card purchases where the gift cards were given to someone in another country. It was an obvious scam. I never give my password out, have a very complex password, and am extremely OCD about my computer and spyware / viruses. All attempts to contact Apple for a refund were denied. After multiple e-mails back and forth, it was clear they weren't going to give me a refund. At the time I had authorized iTunes to link to my credit card, and so my credit card company denied my claim indicating I had authorized iTunes transactions and had to take it up with Apple. I filed a BBB report, which was "resolved" according to BBB simply because Apple responded to my claim with some computer-generated lame reply. I was screwed out of $100.
I'm also an Amazon seller, and I sold a PS3 that was working perfectly (and I shipped it with EXTREME precaution). The buyer indicated it was broken and wouldn't work at all, which I was highly skeptical about, but I offered a full refund including return shipping if he would send it back. He refused to send the item back at first, and tried to take advantage of some Amazon policy loophole where if the item doesn't have 100% of everything advertised on the product page, the buyer can in many cases obtain a refund without even sending the item back!!! Anyway, I fought and fought and fought this, and eventually Amazon persuaded the buyer to send the item back. When I received it back, it worked perfectly! Clearly the buyer was trying to get a free PS3 using this Amazon loophole. I got the PS3 back, but I was out shipping, return shipping, and it caused a ton of headache and of course the buyer left negative feedback!
In each of these cases, I learned very valuable lessons and am a lot more careful now with how I buy and sell online. And while I know that "life isn't fair," and crap just happens, as it has with these issues above (and many more), I also understand how frustrating it can be when you are trying to do things honestly and fair, and you are constantly taken advantage of by other people who just want to screw you over.
I try not to sweat these things much anymore, and just have an understanding that there are a small percentage of cases where I will get screwed out of some order / sale online, but I still fight certain cases very aggressively, when I feel someone has been extremely dishonest and/or disrespectful of my time and money.
I think the real sad thing here, is that there are just SOOOOOO many people who have no problem with screwing over other people for their own personal gain. It is very disheartening, but that is the harsh reality we live in --- the internet is an amazing thing, but it allows fraud to easily occur with very little ramifications for the parties committing it. Good luck to those who actually try to fight it!