DEBITING WRONG BANK DETAILS

I have made attempts with Telkom to change my banking details from FNB to Tyme Bank numerous times over the past 6 months. Reason being I no longer have an account with FNB meaning the account details on their database are outdated however I am still being charged a 'payment rejection fee' every month for the past 4 months because Telkom is still debiting that non-existent FNB account.

Each month, for the past 4 months, I have been making manual payments from my Tyme Bank bank account settling each bill days before the debit order date. The funds are received by Telkom reflecting payment dates BEFORE the dbeit order date however I am still being billed 'payment rejection fees' despite the bill being settled before the debit order date. R202.00 is a lot of money every month for something you are complying with.

I do not know what other steps to take because Tyme Bank is a registered bank in South Africa and they are receiving payments from my Tyme Bank account so why can I not have my banking details updated to Tyme Bank?

I need an answer soon or I am cancelling services from Telkom at the end of this month