Billing for Data I never used

I have a contract with Vodacom and on the 18 August 2017, I requested a 100MB month-to-month bundle to be added to my monthly bill which Vodacom did. On the 19 August, I requested another 250MB month-to-month bundle to be added to my monthly bill which was not added onto my phone, including the 15MB I requested on the 20 August and the 100MB on the 28 August. The problem I have now is that Vodacom wants me to pay for all the requested Mega Bites that were never added onto my phone. I have tried calling their customer line with no help and I have also gone to a Vodacom store in BlueRoute Mall still no help. Because it doesn't make sense to me to pay for Data Bundles I never used.

Additionally, Vodacom feels like they can charge you for whatever they want and because they automatically deduct money from my account (Debit Order) there's nothing I can do to prevent that from happening.