Tracker *****ing from me

So i have been a tracker customer for many years using what i thought was a contract of R199 per month. I recently discovered that i was being billed between R600 - R800 per month for "message notifications", a charge of around 80 cents per sms recieved , when i enquired what that was related to i was informed that each sms sent was for ignition on and ignition off notifications. I have never requested this service nor have i ever enabled this service from my side so tracker has essentially been *****ing from me every month , and the worste part is that i have never even recieved the sms's they claim they are billing me for, had i recieved a sms notification each time the car was started or stopped i would have cancelled that immediately. Tracker is *****ing from its customers.