Their TOS allows them not to pay you, if they didn't make a profit off your traffic (even if you followed all of their rules and your traffic was 100% legitimate!)
All the proof you need is here in this thread (complete with quotes from TOS and posts from un-paid webmasters):
https://gfy.com/fucking-around-and-business-discussion/730001-ctc-live-05-click-plus-50-signup-win-1000-thread-28.html
P.S. Ironically, they also didn't have enough decency to even pay the "winners" in that thread! ... And now they're getting into the medical insurance biz out of all things.