I am seeing this now as harassment

I had the worst experience with Cartrack, my number was added to Cartrack database without my consent to be contacted if any vehicles at the dealership's battery were running down - This was all good and well at the time, I did not think anything of it at that stage. Now that I have left the dealership more than 2 months ago I still get phoned in the small hours of the morning. I have requested Cartrack to remove my number but after several requests, it still has not been done. I phoned Cartrack this morning and it was the worst experience of my life. The phone was dropped on me twice and the third time the phone call was placed on hold till I was forced to redial. Although my number was added to the Cartrack system without my consent they refuse to remove it as I do not have the authority to do so. (I did not authorize my number to be added in the first place) The Cartrack representatives continuously stated that I was not authorized to do so and when I requested a manager's contact information they refused to provide it by quoting the POPI Act to me. So how am I protected by the POPI Act that you are so freely quoting to me, where is the document that I signed consent to use my cell phone for Cartrack to run their internal system processes? All I want is to have my number removed as requested as I am seeing this now as harassment.