Unauthorised debit orders

I have a problem of unauthorised debit orders on my account for yhe past three months today they took R1600 on my account I can't dispute it. I called the bank they told me that it can't be reverse i have never signed a mandate to any of this debit orders.

It's unfair to have an account that keeps on debiting money without authorization. I tried calling the companies that are debiting but they don't exists were is my money going honestly.