Cell-C Marketing Fiasco

Spam alert: I got my second unsolicited marketing call from someone claiming to work for Cell-C today. The caller line ID shows a Durban number, 031-333-6700. I explained that I have already put my number on their "Do Not Call" list and the agent asked me to hold and then hung up.
When I called the number back I was told that the number belongs to Elite Mobile, a large Vodacom supplier, and they assured me they have nothing to do with Cell-C. They did, however, explain that there is a Cell-C office in the same building, but couldn't explain how or why the call would show with their number.
The lady at Elite Mobile who took my call seemed to know a lot about Cell-C using a database of randomly generated numbers, however. Presumably she had had to deal with complaints before.
I contacted the Cell-C Media Relations manager, Vinnie Santu on 011-324-4919 and explained that the call violates the ECT Act because I have already informed the previous Cell-C agent to put my number on their "Do Not Call" list. My guess is that the agent had no idea what I was talking about and so exposed Cell-C to the legal risk they now face.
Either Cell-C is putting a false number on their caller ID, or Elite Mobile is partnering with them, or it is going to get a nasty shock when their phone bill arrives. Either way, it doesn't reflect well on a company that my brother used to rave about and is now completely fed up with.
It took a bit of research and dead ends to get through to the person in Cell-C Head Office who handles direct marketing. I kept getting referred to the Cell-C Service Provider, which is not what I wanted. Later "Marlow" from the Cell-C head office phoned to say that Cell-C doesn't do any direct marketing and she would contact "Sue Kennedy" to sort this out. It seems that very few people in this voice-mail organisation have any idea about the ECT Act or what a "Do Not Call" list is. Surely they have contractual arrangements with the people who sell their products? It appears not. I guess an organisation this big simply has no idea what it is doing, other than losing customers.
Update: I got a lame apology to my HelloPeter complaint, but no particulars on who is legally responsible. Why am I not surprised?

HelloPeter complaint