Extremely rude marketing manager

I work at a Advertising Company in Johannesburg and we received a call regarding marketing. The receptionist was told to say that we are not interested, but when she did so the woman started screaming at her that she is ****** during which our receptionist put the phone down. She phoned back and screamed at our receptionist and the call was transferred to me. I tried to find out her reason for calling and she just continued screaming at me and started swearing at me calling me a f*&^ing ******. According to her the reason we are not interested in what she is selling is because she is black. She refuses to give her name or to put me through to the manager or owner and told me this has nothing to do with them, she can do her job any which way she pleases. I will never do business with a company if that is the person on the other end of the line. I still don't even know the reason she phoned because if i try and phone back to speak to the owner or manager she swears at me and slams the phone down in my ear. I would appreciate if the owner or a manger can call contact me.