Unauthorized debit order

Last month I received a call from one of the consultant @ Standard Bank Insurance Brokers, selling an accidental plan. I spoke to the lady (I don't remember her name) and I CLEARLY instructed that I don't intend to increase any of my debit orders because I have financial strains. But guest what, today one of my debit orders increased by almost R71 of which I didn't authorise as per our conversation. Today I called Standard customer three times and unfortunately I was not helped.