Flagship Studio, makers of Hellgate: London, and currently developing Mythos, are apparently closing down for financial reasons. I didn't post the first rumors of it yesterday, but now at least the new owners of the intellectual property are making statements to that effect, even if Flagship Studio itself is still in denial. Players report that the Hellgate: London account page is down, so you can't cancel your subscription. I am not a lawyer, but I'd think that in this case you could tell your credit card company to refuse payment, if you really want to. But then, both Hellgate and Mythos could be run in the future by the new owners, so I wouldn't panic until the servers shut down.
I think it is fair to say that Hellgate: London wasn't a huge success. It was nice enough to play for a couple of hours, but didn't really have what it takes to justify a monthly fee, which in any case was relatively high for a relatively small upgrade from the non-subscriber version. Mythos looks a lot better, but is still in beta. I sure hope somebody will make the effort to apply the final touches and release that game. Somebody will soon make a statement blaming WoW for the failure of Hellgate: London, but the truth is that game companies fail if they make mediocre games, with or without Blizzard. The only thing you can blame Blizzard for is showing the world that quality games *can* be made.