Change of bank details impossible with Vodacom

I try to change my bank details for the past 3 months with Vodacom, but they make it impossible to do. When you phone, they put the phone down and direct you to their Chatbot Tobi. When you do it on their App, there is technical issues for the FULL 3 months. How can it take so long to sort something out?? When the DO doesn't go off, they charge you interest. WHY???? You make it impossible to pay when changing bank details.