No idea, but it's happened before and they came back. Credit card expired without them noticing? Hard to say. I don't think they break any of the hosting providers rules.
What's funny is my last post there was replying to someone who asked how long the site would be around, and I said as long as whoever is paying for it keeps writing the checks.
Last activity on the Facebook page was in June, no updates there. I assume it will be back once things are sorted, and if not, someone in the know will show up here and explain what happened.