I don't have an account with Truworths

I don't have an account with Truworths. But it so happened that someone gave my number as a second option. People from truworths call center were calling me every day demanding payment that was due, when I try to explain that I don't have an account with them, they would shout at me. And also send messages to demand the money every single day. I am not happy with how they conduct their business, and the person who has and account with them is a pensioner, so I don't get why they allow a person who only receive R2000 a month to have an account with a higher buying power which requires a payment of R1300. What they use for groceries, funeral policies and other living expenses