No agreement/contract, monthly charges and daily harassment

I purchased a vehicle in march 2021 from a dealership. At no point did the name Cartrack or tracker of any description get mentioned throughout the purchase procedure. I have no agreement/contract, I have no debit order authorization document nor did I authorize the installation of a device. After a review of my Bank statement in December of 2021 I noticed a debit order of R140.00 being deducted. I contacted Cartrack and explained to them exactly what I have mentioned above, to no avail. After no action on the part of Cartrack I put a stop order in place and removed the debit order from my account. Now I am being Harassed and threatened daily. I have emailed Cartrack on several occasions to *** without any feedback or action. I question the legality of engaging in business like this. I cannot accept that a company can just help themselves to somebody's money without an agreement in place. To make matters worse, the company I work for uses C-Track for our fleet of vehicles and trucks and I could get a subsidized C-Track account through work. As such why would I want a Cartrack account or device?