Vodacom giving my number out

I received a call from MONDO (or something like that) saying that VODACOM has givEN consent to them to access the vodacom data.... VODACOM did not ask for my consent to just hand out my number... that is ******* and is starting to get on my nerves. every day i am getting calls from company who are receiving my number from VODACOM. I will take action if this matter is not dealt with ASAP. My details are personal and ONLY FOR VODACOMS use. not to just hand out to every company they see fit. I WILL BE LEAVING VODACOM because of this, this is wrong of VODACOM. in the contracts i sign i make a note of saying that VODACOM will not just give my number out when THEY feel the need to. Pathetic.