sports*monster eBay seller cancelled purchase from auction, and then reposted item in a attempt to get higher bid.

I won an eBay auction for listed beginning price of item. I was the only bidder. After winning the item(shoes for my 3yr old daughter) , seller cancelled purchase citing the reason that I asked him to do so. Apparently this is a valid reason to cancel a auction purchase, and eBay allows it. Doing this allowed seller to circumvent accountability. He reposted item in another auction and sold it for a higher bid this time. I called eBay and they informed me that since the item was never purchased I could not leave feedback on his account. I am pretty sure the seller is aware of this. I don't understand why a grown man with an online business would need to make a couple extra bucks so badly that he would con a customer out of business that's promised through the online auction platform.