Bank Details Change

I have recently changed bank accounts (still with FNB) I called the various departments to have my banking details updated, I'm told that it cannot be done as I would like to have my business account debited. How can this be when all my other service providers have already made the change. I send an email to *** on Monday(4th) @16h47, got an automated response back confirming the turnaround time is 2 days. Today is the 7th and I have not had 1 person reach out to assist me. Do you want me to default on my payments? Do you want me to get a bad credit score? I need assistance to get banking details changed, please- is that too much to ask for? Everything is noted in my email sent on the 4th. PLEASE! I would hate my debit date comes and I'm still struggling to get my a simple bank account change done.