eBay sellers can cancel an auction for pretty much any reason without any worry about eBay doing something about it. That is eBay's policy. They don't care. I usually have auctions cancelled on me when the seller sells the item privately while the auction is in progress. Once I emailed a seller who cancelled an auction for a chip I really wanted. The seller told me that someone offered him a great deal by email and he accepted. I asked about the price and then I told the seller that I would beat it and I got the deal. It never hurts to ask. Morally, cancelling an auction is not a great thing to do, but the practice is wide spread.