Ms. DtG - not sure if this helps, but I've been using C2it for at least 6 months now, and haven't had any messages from them or shut downs. I went through a little period where I was so busy at work I forgot to transfer for a while, so my total this year is around $17k or so - soley from my cc to c2it to my banking account.
I always make sure to leave a couple of hundred dollars in my c2it account at all times (anywhere from $200-$500). This way, c2it earns interest on the float, I get a ton of points, and I also make out on the other end of the float, because I'm earning interest on money I transferred out to bank account, but haven't yet paid to my credit card to cover the orignal c2it transaction.
I haven't hit the $20k mark yet, and will likely wait until 2003 to do any more transactions, just in case.
Good luck!