FNB:Unauthorized debit order from REARGENTUM

I experienced unauthorized debit order of R98.99 from REARGENTUM which I don't know. When I called FNB contact center to stop this transaction he told me they cannot do it I must call the service provider. I DO NOT KNOW this people, this is *****.They are indirectly telling me my money is not save with them. You better call me and STOP this transaction to never happen again. I wonder what is the purpose of Debi Check if some debit order will just go through without being approved. My email address is ***

Kind regards, Abel