You don't have to bet on the matches. The competition is free for everyone.
It's free to participate but you may never get your free bet even if you correctly predicted results.
I have been dragged with FortuneJack support and email for days like I won five million dollars, and it's really hilarious.

I won a freebet some time ago from a competition here on bitcointalk and after some chatting with live support, they credited my account. It can take some time, but as Pmalek mentioned, you will get your freebet.