Forced to save credit card details on app

For some reason certain bundles on the VodaPay app can only be purchased by credit card or VodaPay wallet. Others can be added to my bill. I used to be able to add all purchases to my bill on the old app. Vodacom cannot explain why they made this change and they supposedly also cannot log a request to have this rectified. I am simply told to "buy another bundle" or "speak to a consultant to process the purchase" (so I must make an 18 minute phone call every time I want to buy a data bundle?). It makes absolutely zero sense. Also, the only way to purchase with a credit card is to store your credit card details on the app. This is a security risk. So, I can no longer buy the bundles I want by adding the amount to my bill, which gets deducted from my bank via stop order. I also cannot do it by entering my cc details every time - it MUST be saved on the app. Is Vodacom trying to make dealing with them more difficult and risky?