What's happening with Telkom

I had a mobile contract with Telkom which was due to end on the 31st of January 2025. During December Telkom debited my bank account earlier that the date we agreed on without making an arrangement with me, when they did not find money there , they charged me a rejection fee. On the 27 of December they debited their instalment plus the rejection fee .I disputed this until I finally agreed to pay the rejection fee. Today I phoned to make an arrangement to pay that fee since I don't want them to debit my bank account anymore, the consultant told me that they can't stop the debit even though I called them before. How is it possible that a big company like Telkom can't make payment arrangements with their customers , To top it all she tells me about a balance that is more than the one that is on their invoice 🤷🏽. Please assist me Telkom wants to **** me . What kind of service is this. They treat me like this because our contract has ended. I spoke to other people also and the say it's what Telkom does to customers.