Debit order switch

I switched my telkom debit order I think on the 2nd or 3rd of October and on the 4th I received an sms confirmation from telkom saying that they have received my new banking details I get paid on the 25th of each month and when I checked my app Telekom did not debit on the new account but they tried to debit on the old and when I called still on the 25th the agent I spoke to said her name was Mangisa and I must send the proof of the sms she gave me her email address and promised to create a case for me I waited until the next day there was nothing on my message I called telkom again and mind you, you wait for someone to pick up over 15 minutes I asked to speak to the person I spoke to the day before I did not receive any help and the person I spoke to told me i'm liable to pay the insufficient fee and my question is I changed my debit order in time I received confirmation from telkom that it is done why should I pay a fee for something that telkom did I'm not happy about this and what annoys me the most if you call and ask to speak to a team leader they are always not available one agent promised to ask the team leader to call me back even today I'm still waiting