Debit order still taking place after calling to cancel the product three times

I’ve called Vodacom on three separate occasions to cancel my month to month Fibre deal. 1st on the 7th of June then the 30th of June and today. My account is still be debited. I was told that an investigation would be conducted after the second call. Upon calling the third time the lady assisting was rude towards me and the situation still hasn’t been resolved.