A company can enforce new T&C's any time. A company's terms always state that it is the user's obligation to review them for updates (didn't you watch that South Park episode a few weeks ago?).

So, each time you log in, you have agreed to the current terms. It has nothing to do with when you registered initially. Thus, you can throw whatever fit you want, but you won't get your fees back, if you complain. Furthermore, if you are in any way in violation of their terms, you shouldn't be doing this anyway.

I'm all for getting free points, but you can't do it in a furtive manner. I haven't reviewed the terms, but I highly doubt they are permitting setting up two accounts and sending yourselves money. No company that has raised VC dough is going to allow that, and if you were dumb enough to go ahead and do it, you deserve to be charged a fee.