forced into 3 year no option to cancel contract

a bunch of unhelpful people. i was sort of forced me to take a 3-year contract out with cartrackby king price insurance. I only realised it was a 3-year contract when my brother in law informed me about it. on the day the tracker unit was fitted. the next day I contacted king Price and cartrack and informed them that I do not require the tracking unit for 3 years because I am in the process of selling the car. I was under the impression that there is a 5 day cooling of period with online or telephone contracts. I was told if I want to cancel the contract I will have to pay R2650.00. or I have to pay the monthly installment of R69.00 for the next 3 years. this was in May 2020. then on 24/09/2020, I get an SMS from cartrack stating that the unit was tested and found to be faulty. so now I am paying for a faulty unit.