A crime syndicate at work?

This is my Vodacom experience : in July 2019 I responded to a offer advertising a 5G + 5G Wi fi data package @ R129 /month. Without warning in April 2019 I get a call informing me that I am R469 in arrears - which coincided with the non renewal of the data package for April. This was amazing and actually ****-like because my bank statements reveal that payments were fully up to date. At this point it is necessary to point out that I do not recall getting a copy of the contract I signed at the dealer, and I have to date, not received a single statement/invoice from Vodacom. I opened an account about a month after the Vodacom contract was activated but made no attempt to notify Vodacom that that details of my bank account given at the time were to be changed because it was not my intention to alter the debit arrangement that I had consented to at the signing of the contract. This would be completely unbelievable were it not a fact :- when I contacted Vodacom for a copy of the contract which I signed, it was refused unless I could provide a copy of my I.D. - and yet somebody who was not a signatory to the agreement was able to 'update' my banking details without my authorization. It turns out that I have as a result been charged a penalty fee of R100 every time an account of mine has been unsuccessfully debited. Can somebody tell me which law entitles Vodacom to charge a fee of R100 ? I think that if it was not for the willingness of the various structures appointed by the state to pass the buck and instead have the will and determination to do justly and deal with the numerous acts of non compliance with the Consumer Protection Act by this Service Provider, Vodacom would be walking on hot coals! I can only hope that there is a God and that vengeance will be His to repay. Thank you.