On Air constant phone calls!

After reading many reviews and their numbers coming up on my cellphone as spam, I block all their calls. Yesterday however, I answered as the number came up as Multi Choice. I made it clear that I am not interested in anything they had to offer and that they should remove me from their marketing database, which is my right under the new POPI act. The Call Centre Agent became quite snotty and wanted to know if I am not interested in their products can I at least explain which products I am not interested in and why?!!! I just ended the call. As a consumer I can opt out of any marketing without having to give a reason for or explanation as to why.