MTN forced debit orders to get more money out of me

MTN has implemented a forced debit order option which is a complete ****. I have been a loyal customer for decades, and I pay my account cash every month, as soon as the money is ready in my account (the date of this availability changes with each month). The problem is they have now forced a fixed date debit order on my account, so it can never be paid properly. Worse, they pick a date that is definitely not when the money is available (since it is available on a different day each month), and then the cheek of it is they charge an additional R11.50 for the failed debit order. This is basically a money making **** on their part to get an extra R11.50 out of me each month. After the debit order fails, only then does the app update to show the amount of the statement and then I can pay it by cash, along with their disgusting R11.50 additional charge each month. In addition, my bank also charges me a fine for a bounced debit order. I can't believe they have insisted on doing this to me, it's horrible. I find this completely *********, I've tried phoning and going into the store and they outright refuse to change it from a debit order back to a cash account. I can understand if there are some customers who miss payments and they might want those customers on a debit order, but I am a good and up-to-date customer, yet a debit order will never work with me. I don't have a single account of mine on a debit order, until now with MTN who insist on it and won't change it. It is so inconvenient and *********, I am even considering cancelling all my contracts with MTN, just over this one thing. If they could just remove debit orders for my account and put it back to cash as it always has been right from the start with them, I will be happy and will be able to pay it every month on time as a cash payment.