Penalty fee for canceling the tracker

I am having tracker on my car that I sold last year, so now I have trade in that to new, of the new has tracker for the same company. So I have requested them to cancel the subscription for the old car and proceed with the new one. They said I have to pay penalty fee for R1000 because the contract was for 3 years. So why must I pay something that I don't have of which is not like I am just doing the cancelation, I am still with the company but with the new vechile. Can you help me to resolve the matter. I cannot pay for 2 trackers of which I have one vechile.i was not informed before