No reply from FNB

In January FNB deducted a Debit Order. They were supposed to refund me, but took the money of my account again causing an overdraft on my overdraft!!. I have been struggling since 6 Jan to have this rectified as there is accounts that needs to be paid and I actually paid the amount less this month as my account was in a minus. The last was that they need to get instruction from me to fix it. I have send emails on emails and screenshots. CAN SOMEONE PLEASE HELP ME!!!!