Will people STOP erroneously saying that a signature on a document is tantamount to a contract. It simply is not!
OP, I really feel sorry for you. I remember as a 17 year old, I spent all my savings on a car. It broke down and (whilst I can't remember the ins and outs) the repair garage basically held my car hostage for weeks whilst attending to more "essential" repairs.
I was a mixture of too polite, too unconfrontational and too ashamed to do anything about it. When my dad finally worked out what happened, he marched me over there and nearly had a fist fight with the garage owner. It did not good (it rarely does), but my dad bailed me out, paid the fuckers off and I got my car back. I don't think I have (knowingly) been ripped off since. Sometimes, you just have to go through the experience to make you wise to these antics.
Point is this: everyone (and I mean EVERYONE) gets ripped off at least once in their lives. If you don't have the stomach for a long and time consuming fight with them, at least take solace in the fact that you still have a membership which you can use, and that the total exposure was only 10k. For what it's worth, I use CF and I actually think they're pretty good.