Cartrack Cancellation Fee is A ****

I am fed-up with Cartrack client service centre. Receiving calls almost everything and asking for one and the same thing. I cancelled my contract since my car was traded in and it was sold to the dealership of which I do not even know which will be the buyer thereof. They call me almost everyday asking about about the cancellation fee due on my account. I refused to pay since when I took their services on inception they never mentioned anything about a cancellation of R2,8k , I therefore requested for the recording stating that they did mention and also signed terms and conditions and it’s been 3months now they are failing to do so. I am tired of receiving calls daily having to explain one thing. They sent me blank T&C’s without any signatures, so where was the agreement between me and them agreeing to the cancellation fee? I AM NOT WILLING TO PAY SERIOUSLY SO!!!