Cancellation fee paid...they took more money

I cancelled my Vodacom contract and paid the Cancellation Quotation fee in full. This was sent with conformation of payment back to Vodacom. I got an sms on my Vodacom number to say the cancellation is processed and my number will be moved to prepaid. Which it did. The cancellation fee was the subscription airtime for 5 months as well as the handset fee outstanding. It all came up R2800, fully paid. Come month end they place a debit order for ANOTHER R1200! When i query it, no one can answer me, one says its the outstanding subscription airtime, which I have paid for already, another says its the handset, which was the other half of the paid amount already! No one knows what is going on or WHY VODACOM TOOK R1200 from my account without MY concent. No communication from Vodacom saying there might have been a mistake or there is more money outstanding. I even paid R99 to cancel the initial debit order i ise to have with them. And Vodacom just takes that amount with such ease as if its their own bank account. I am appaled and will take this further as there is a discrepancy between an invoiced amount that was paid and Vodacom just takes more! This not only affects my rights in the CPA but also my trust in this company!