ADT never acts in good faith

After 4 years of being with ADT and now when I cancel because I am not happy that my house was broken into and the only reason they give me is I should've made provision for them to access my premises, which was never discussed with me when I signed. I got a call from their "community liason officer" who claims I'm on a rental system as it was installed by a 3rd party and ADT bought it from the 3rd party, now 1. I never called any 3rd party, I signed up with ADT 2. The person who signed me 4 years ago informed us that on cancellation, ADT will only remove their radio transmitter if it's after 3 years, now I'm being threatened that they want to remove everything or else I pay them R3500, what **************** is this by a whole security company, surely they've recovered whatever it cos them to instal in my property. I have never experienced such bullying by anyone, let alone a company that was supposed to be reputable. I will never ever recommend ADT to anyone and whoever I have recommended, I have informed them of the shady dealings by these company. The worst company ever!!!!!