UNAUTHORISED DEBIT ORDERS!

I am inundated with unauthorized debit orders on a monthly basis. Does anyone from FNB care to tell me where they get my account details from? Or who authorizes these debits? I once inquired with the team of bankers – Reuben Singo- who bluntly told me that they (FNB) cannot with cer*****y say where my details are retrieved from. He said the suggested solution(reversals) was the only current solution. He said this was the solution for the current reality, bank is aware of the phenomenon and is currently formulating strategies. And that I have all the right to implement any majors necessary to protect my interests; however; this was the resolution available for FNB customers. I have just received another sms of a debit order that is due to run from account!! Im ready to report this to the ombuds!!!!!!!!!