Vodacom ***** in the night

There shouldn't be any rating. I cancelled my Vodacom cellphone contract as at end December 2017. I was billed, as they advised, on a month to month basis later. I contacted them and advised that I specifically cancelled the contract and will buy airtime on a prepaid basis. This morning another debit of R577-00 goes off after having cancelled the contract, contacted them again to make it clear that this number should now only be prepaid and not billed on a month to month basis for my usage. This is outside of my budget and my debit order for my vehicle financing will now not go off hence my bank will charge me extra costs for that too. I tried numerous times initially after having sent written cancellation to cancel my Vodacom contract to call them to confirm this telephonically. I was unable to do so. I feel they are ripping people off even after insisting that they don't have permission to bill, even month to month, as I would like to manage the sim card myself by prepaid, buying my own airtime should I wish to do so. You are no match to Cell C.