Unauthorized debit orders continually going off my account

I have had unauthorized debit orders going off my account for the past 2 months, sometimes twice a month. I have spoken to numerous call center agents and none can advise me on a solution. All I am told is to stop the debit order, which I do but these ********* *****ing my money just change the reference and debit again. Should I close my account at FNB and move to another bank? Is that the only way to prevent unauthorized debit orders FNB? Why is there no way to verify debit orders?