Unsatisfied vodacom customer

I am very disappointed with the service I got from Vodacom. Money was debited from my bank account without me as an account holder being told about it. According to Vodacom I can dial the *135# and make changes to a contract, whether it's adding services or subscription for data or airtime even if I'm not the account holder. It will be added on the contract and invoiced and the account holder is held responsible for such a payment. How am I as a customer protected when ******* like vodacom can debit money from your account without me giving consent to do so.