Harassing clients through "Unknown" phone calls

<p>I think as a client/customer of Vodacom I have the right to choose when and if I should receive unwanted marketing phone calls from Vodacom. Even more - they should at least have the decency to display a number and not to instrucs staff/marketing sub contractors to dial from computers with the number displayed as "Unknown. I want this investigated and I want to know what will be done to discontinue this practice.</p>