Excessive billing

Vodacom constantly bills me incorrectly which results in hours of frustrating calls. I have emailed the CEO Shameel Joosub and he just refers this to Rudzani who does not seem to have any decision making powers or abilities. Initially I was incorrectly billed for an upgrade that was cancelled in time, this took about 2 to 3 months to resolve and numerous phone calls. Now I am being billed for a number for which there was no contract. Each time I get an apology and no consideration for the time and frustration of resolving issues that Vodacom creates. I feel that this is disrespectful of my time and the issue does not take 1 phone call to resolve. I am a pensioner and any additional charge affects me, but they just take the money from my bank acc and I feel so helpless. How do we as customers stand up against this *****ulent behavior. Corporates just constantly feel that the incompetence is acceptable and the customers should just have to accept this.