There are a number of legitimate reasons to close an ebay auction early, including, from ebay.com: "You made a mistake when entering the listing, starting price, or reserve amount."
Reference at ebay:
http://pages.ebay.com/help/sell/end_early.html
I do think a seller has some rights before an auction ends, and its hard to judge someone without knowing all that they know.
However, if an auction actually finishes, that is a different matter; it should at that point, unless there are specific listing errors or fraud, it should be a
legally binding contract. But Sedo does not work that way.
I bought a domain a couple months ago at Sedo, by accepting the buyers price, so that should have been a done deal. But the seller changed his mind - possibly because of interesting news that had recently appeared; so the seller begged Sedo to cancel the sale, claiming he made a listing mistake - and Sedo agreed. It really bothered me, as I wanted that domain a lot. I am not going to say the domain here, and I am not going to criticize the seller - who knows, he might have had a good reason - but I am very critical of Sedo that they would cancel an auction without any good reason.
Therefore, Sedo's claim that a sale is a legally binding contract does not ring true to me. And they did not release the sellers name and address to me, as they are supposedly going to do when someone might want to make a claim. So they were doing someone a favor, and its just not right.
Kevin