beware for call center agents

Hi i had a call from an agent from tracker calling me and offered me a tracking unit for my vehicle, They offered me a good deal that if i take the tracker that day its only R99 per month unaware that its a 3 year contract. its not that am not happy with the service its just that my vehicle is sold and now after 6 months when i called to cancel the tracker they tell me that am on a 36 month contract with them and if i have to cancel i need to pay the contract off. the new owner doesn't want to take over the tracker so i explained tracker that i cannot pay for something that am not using. the manager from tracker called me and said if i don't pay he will send hes lawyers to recover the money i had plenty other tracking companies before tracker and when my vehicles were sold the tracker was cancelled PLEASE PEOPLE BEWARE OF CALL CENTER AGENTS THEY CALL YOU AND YOU DONT REALLY UNDERSTAND WHAT THEY SAYING BUT BECAUSE THE DEAL SOUNDS GOOD WE ACCEPT IT AND THEN LATER ON WE FIND OUT WE ARE IN A 3/4 YEAR CONTRACT BASICALLY THEY SAID THERES NOTHING WE CAN DO WE ARE JUST FORCED TO PAY FOR SOMETHING WE NOT USING.