Debit Order Reversal Horrible Experience

Since 08:30 this morning I have been on call with FNB. Fisrt you get an automated response and you are not able to get through to the consultant. You are sent a link to banking app which you are supposed to use to reverse the debit order. All this is using my data and finally when you get the app you are not able to dispute the debit order. I have tried everything secure chat, calls, banking and 3 hours later no help.

80% of my salary was deducted and I want this money back. This is a big financial strain from my side can someone help.