Poor customer service

A company Named On Air representing Dstv Multichoice called me yesterday regarding decoder upgrade, I indicated that I am not interested. The same lady calls me today with same information, I tell her I am not interested as I indicated yesterday,yho the lady start yelling over the phone for not wanting the upgrade. DSTV kindly deal with your consultants. I have a right as a customer to want to chose to buy your product but I can't be forced your products. Can we be respected as customers. The company contact no number***