The pay as you go billing is very strange. First I did not know that you could "stop" in the middle of a month. So for last year, we would just activate a "month" and then it is supposed to turn off automatically at the end of the month. However, when they bill it, it bills for the following month, until it sees you didn't use it and it "catches up" and removes the month you didn't use.
In the meantime, you get bills for these months you didn't use and then the past due bills when you don't pay them. Like I said, eventually it catches up and they remove them but I did kind of find it a real pita to deal with.
I'll have to look into this turning it off on the website thing and back on, since at most we might use it for a solid week, followed by a couple weeks of not using it, etc.