Complain

I feel, I'm being harassed by this Company. I have been telling them that I'm cancelling their service/ tracker and I am told of the cancellation fee tof R2600, that was initially not mentioned, I was told, I would be liable for a cancellation fee, should I cancel within a year, and it's been more than a year now, they reckon they won't cancel the service, should I refuse to pay the cancellation fee