Paying of cancelling

I've been with Cartrack for more than a year now and I have 3 vehicles with them... upon selling my 1 car I contacted them to cancel only to be told that I have to pay R1700 cancelling fee what ****... I'm still on their books as a client I just removed the one car..... totally just a catch and honestly that was not told when I signed up!!!!! Its all about the R99 a month for a car that they focus on but yes again always a catch>>>>>> totally disgusted!!! when my next 2 cars time passes I'm switching.....