Car Service City painted my car window with their company name after servicing without my consent

I took my car for service at Car Service City in Illovo Johannesburg. I signed it off to Jared who was responsible for the vehicle for the day on 18/01/18. Upon completion of the service job I paid Car Service City the full charge and did not notice that they had painted my back window with their company name " Car Service City". I did not consent to having my vehicle painted and branded with someone else's name on it. This is not part of the agreement and I did not consent to this. Who gives Car Service City the right to mark my property with their brand. As a small size, young, single lady who needed a service, was I taken advantage of because I was a soft target as a single female? Was my car marked for them to track me as an easy target for hijacking? What is the reason for someone to go out of they way and paint your vehicle with their brand?

To my knowledge the owners of private vehicles that get branded by other companies for marketing receive an agreed monthly inventive. Car Service City how much are going to pay me for branding my personal vehicle with your company name?