Unathorised debit order deduction

Hi, there has been an amount of R145 that has been debited from my account monthly with the ref: BESTINTERNBI-***0-2. I called my bank for details and was told it was a deduction by Santam, I called Santam and was told that it is not their reference as it starts with a J. I was given the number *** to call to ask for Nadia Fourie, I called and there is no answer, I then called the head office number *** an there is also no answer. I have been reversing this amount but need to know how they have my details and what it is for?