Cartrack stop calling, I am already your client

I am already a customer of Cartrack, since 2019. Starting from last year, I have been getting a lot of random calls from Cartrack telling me about what they can do for customers. I have asked the company to stop calling me, in relation to this but the calls never stop where I will be called on a daily basis about their service offerings. These calls are highly irritating to a point where I am now thinking of actually not being their customer anymore.