Rewardco - anothr call centre selling cell phone contracts...

I'm really frustrated at the number of calls I receive from noisy call centres with semi-literate people reading from scripts, trying to sell me a cell phone contract. I just received a call from Jevon at Rewardco who totally lied to me when he claimed he was not trying to sell me a new contract. After 10 minutes of listening to him read his script he admitted that in fact he had lied and he put the phone down on me. I get at least 1 of these per week and it's a complete waste of time. They tell me that they get my number from Vodacom but since this isn't an 'application provider' it doesn't appear to be covered by the WASPA code of conduct. What can we do about this? Is there not something that can protect a consumer from this voice spam (actually much more expensive to me than email spam).