It is definitely fishy, but I'm pretty certain your claim is legally unenforceable (I calculate and testify to damages in litigation). He said that his assistant put the auction together and he (the seller) intended to have a 75k reserve, but his assistant made that the buy it now. He said he intended to have an 85k buy it now.
He also told me that he had lots of interest in the car, which I think surprised him. He said two dealers called him and offered him something in the low 70s. After the test drive I offered him 72k, and that is when all of this came out.
I told him that the fact that nobody had bought it now told us something about value, and he said that there would have been a frenzy at the end of the auction, so it is worth more than 75k.
As for the claim that someone tried to buy it now, I don't think that's true, since he would have told me that at 1215pm when we were discussing the issue and my point that nobody had bought it now. The auction ended before 1130am, because I checked it before I drove the car and the auction had at that time been cancelled.
The most recourse I see here is getting in trouble with eBay. But the seller has 0 feedback, so I don't think he will care. Finally, he is a hypnotist and executive coach for a living, so there's always the risk that he hypnotized me and none of this actually happened. But all kidding aside, it is a very nice car. Hardly any imperfections I could see on the body and the interior was nice too. That said, comparable 1.5s have sold on eBay recently for 71k or less (e.g., auction 330594618077), so I don't see this reaching 80k. Heck, I'd just buy #34. Sweet Cars will sell that for just under 75k right now.