Unauthorised Debit Order!!!!

I just received an unauthorised debit on my account: 31 Oct: R30 Ref.S****** An***

I do not have any contractual agreements with anyone for that amount especially not S******. My funds must be returned immediately and you must stop running that debit order. I would also like information of the company that requested for the debit order, this is ******* and unacceptable.