No assistance or help on my FNB Bond

Good day, please kindly assist as I have sent quite a few emails to the help email address at FNB Home loans and, to change my bond banking details and nobody has assisted or come back to me as I sent my banking details and nobody has sent an email, that it is changed. It will be very dangerous to pay my bond at the ATM than it been a debit order. Please this is of urgency and is needed of importance.