Seller changed their mind?

So i was browsing the newly listed razors earlier, and a decent looking goldedge was there that caught my eye. It had some hone wear, more so towards the toe. The scales were faded, more yellow than white. The razor was for a Buy It Now price of $30.00 with free shipping. I almost let it go, but then decided i would like to have another duck in my collection. So i commit to buy, and pay with paypal. A few hours later the guy emails me and says that it was a mistake and that the razor was supposed to be an auction, not a buy it now. So im really disappointed because I feel that that is a really hard "mistake" to make. You have to actually change the auction from the standard auction to the buy it now, and even after you do that, it is presented on a preview screen with exactly how the item will look. I consider myself a nice guy, so im not going to press the issue really, but im curious if anyone else has similar experiences, or would share what they think about the situation. My other DD Goldedge is in way better condition and i found it in the exact same manner, just as it popped up with a BIN of only $45. He is lonely by himself

I had that happen several times on eBay where the seller canceled my bid. I did complain to eBay once and was told it was legal if the seller claims an error in listing. To say the least it sucks. As a seller myself I would never do that. I even mistakenly bid without reading the description. When I noticed the blade was cracked I stuck to my bid and ate my error. It is the ethical thing to do.

You can't really force a seller to complete a sale, just like you can't force a buyer. At most you can leave a negative feedback so that if it becomes a habit they will get penalized for it.
At one point, may be still is, ebay was giving discounts to power sellers if they have good ratings, but for a small volume seller the occasional ding may not matter much. I don't think buyers are bidding more for items if the seller's feedback is stellar and less if it isn't, that's why single infractions don't matter.

I'll probably simply leave a factual negative feedback (e.g. the seller refused to complete the sale claiming error in the listing) and move on.