Accidents and oversights happen, though. They suck, and the company DOES need to be held accountable... but it's like getting a hair in your food at a restaurant. The hair in the food is pretty disgusting, but the way the management responds when you send it back is what generally determines whether or not you'll ever go back to that restaurant again.
In NIS' case, they issued a major public apology for the issue, taking full blame for it and promising that it would never happen again -- and it has not. And while it's easy to say "they should have refunded everyone's money" or something along those lines, a response of that magnitude simply wouldn't have been possible. It would've put them out of business altogether.
As I see it, they did everything they were capable of doing, and I respect them simply for coming out, admitting responsibility and apologizing. That's more than a lot of other companies do in response to bugs, and shows that if nothing else, NIS has a very deep sense of honor and humility. It makes them seem less like a faceless company, and more like a collective of actual human beings. They make mistakes, but they admit to them, and they learn from them -- and it's that humanity, that sense of smallness and closeness, that makes them worth supporting, IMHO.
Just my two cents.