Vodacom - Endless Spamming and Forcing Upgrades

The endless spamming of calls received from companies YOU appoint to trick and force you into upgrades the moment your lines are eligible for upgrades are getting out of hand. After NUMEROUS calls from them you begin to get fed-up and when you push back they think they can return the favor. This is UTTER nonsense. I need to find out how to lay this complaint formally to the relevant parties so that Vodacom can start receiving the fines and stop appointing third party companies to impersonate them and FORCE their way into your finances.