Is it safe to bank with you?

Last year I had a problem whereby some anonymous company was **********ly debiting my account on a monthly basis. I went to the brach and they stopped it. My money was then refunded into my account. A similar problem has started again. The same culprits are debiting my account and when I called FNB call centres I was told to do my own investigations. All they could do for me was to get the contact numbers of that company and I was to do the rest. I never authorized this debit order and I have had no dealings with them. Question is