Cell C unauthorized Debit Orders.

On 5 and 7 September I went in to a Cell C store to settle my to Cell C contracts and Cancel them. I asked the store to give me the full amount that I owe on both contacts. They then gave me two separate amounts I should pay to cancel the two contracts. I then made the payment for both and they told me that the contacts are now cancelled and I don't owe anything on any of the two contracts. Two month later I see two Debit Orders for Cell C go off on my Bank Account, I then reverse them thinking Cell C made a mistake, then the next week I see the two Debit orders went off again, so I call Cell C today and they tell me that I still owe them money on both contacts. I am sorry Cell C, but you won't get a cent from me as I was told I don't owe you anything and the two accounts are closed. I will not pay these amounts!!!