Call centre Harassing me

I am constantly being harassed by Foschini Call Centre. They call to my home and cell phone number numerous times a day. Most times calls are just being dropped. If i do speak to someone and decline what ever it is they selling they become rude and drop the call.

How many times do i have to say NO to a product? Do you not respect your customers. Your call center is worse than debt collectors. If paying customers are harassed this way i don't even want to imagine the harassment received by customers who are late with payments.