DSTV Multichoice Rude and belligerent tele sales agent

I am disgusted with the rude and belligerent attitude of tele sales agents acting on behalf of DSTV. I recently received a call from an agent wishing market something DSTV related, when I declined the agent felt it necessary to forcefully question my decision and while I was responding to hang up the call. In the first instance I do not recall asking to be contacted for marketing or sales purposes, and I am usually pedantic especially about contact via my mobile phone. This is not the way to retain customers.