Can't move my debit order

My son is writing this on my behalf. I've been a faithful customer to Vodacom for more than 20 years now. Through the ups and downs. But simple tasks, the simplest of things, they cannot get right. I have a bank account that I'm planning to close, since it's not needed anymore, and my Vodacom account is one of my last debit orders on it. Looking for a way to move this order has been a hassle and a half. First we go in store, they cannot help we have to phone. Then we phone, I was advised by my son not to give banking details over the phone as this is a very common way to get ****med, so we asked the lady. To her credit, she was extremely helpful and informative about our first request, which is why its not mentioned here, the moving of the account however, she said she understood our concern, and there's a way to do it on the app. We downloaded the app and looked around, there is no spot where we can view much less change it. The website doesn't allow this either. My question is why, why make it so difficult? You promote new apps with a bunch of ways to lend and manage money, but you don't allow the basic moving of accounts? I'm extremely disappointed Vodacom. Do better.