Telkom Mobile terrible service and communication

I changed jobs and went to the Telkom mobile store in fourways mall to change my debit order date to the last date of the month which would have been the date I would receive my salary from the previous employer before the starting the new employment. The agent-assisted me at the and confirmed that the debit order date was changed and it was then debited on the last day 31 March 2023, it then transpired that they attempted to debit my account on 28 March 2023 and ultimately there were not enough funds to pay for the debit order which there was no instructions for. Telkom Mobile then debited again for R682.34, which incurred penalties of R202.00 and against the normal premium which was paid on 31 March 2023. Telkom is not blaming their collections agency and the collection agency is blaming telkom but no one wants to refund the debit order. Telkom needs to address the matter as it is the entity that I have a contact with.