Vodacom sharing private information with ********.

So I have at no time given Vodacom permission to share my personal details, including my telephone number with anyone, yet today I have gotten the third call from some ******* company in Capetown claiming to operate on behalf of Vodacom, and which to my shock and horror had access to all the details pertaining to my Vodacom account. This is in contravention of the ECT act, yet Vodacom seems to think they are above the law. While I have no problems with the service or quality of the Vodacom network, I do have issues with this gross violation of my privacy and I demand that immediate action betaken to remove my telephone number from any and all marketing databases that Vodacom shares with other ******** from time to time, and I publicly now state that Vodacom does not have the right to share my information.