Debit orders done on my account without valid reason

Not one to complain quick, especially not on social media. But I do not get any satisfactory solution to my query when phoning customer care. I suspended my data contract in Sept '19 already. NO more usage of that sim card or account - Nothing. To my knowledge the contract is canceled. No more debit orders go of for the whole of 2020. Now all of a sudden in April '21 I get debited again. For 3 months now Vodacom has debited my personal account. I phoned SEVERAL times (to my own airtime account) to try and understand why this has happened. All I get answered is that they have now (in June without me requesting it) only changed that number to pre-paid and there is a credit (which only today after I phoned again) they will process in the next 14-21 days. This amount is also NOT nearly what Vodacom has already debited. Actually taken my money without ANY valid reason and also not even crediting the full amount. Not happy!