Debiting incorrect Bank after changing banking details and not refunding my miss debit fees.

For the last month and a bit I have been ending emails and talking to consultants of Discovery Bank and yet no one can answer or give me feedback on how they keep debiting the incorrect bank.

I changed my debit order banking details before the debit was intended to go off and when it was time for the debit to go off Discovery Bank debited my FNB account three times and have miss debits for over R345. I have spoken to multiple people telling me that it was an error on Discovery's side but have not received and refund on the miss debits.

I then cancelled my debit order to make an payment due to the fear of Discovery debiting the incorrect account again. Yet to my surprise, my fear was correct, Discovery debited my account again and on top of that it was the incorrect account they debited. That is another R115 missed debit. I also changed my debit order date to the first of every month but they still taking money from my account before the 1st.

I can not express how upset I am as during these times I can not afford to keep paying miss debits due to an error on their part.