Contract cancellation

On 3 November, I called MTN to cancel a contract that had expired in October and was assisted by Nokwanda. After discovering that MTN had debited my account with R539 in November rather than R329 for October, which was supposed to be the last debit order, I contacted MTN. Thando, who assisted me, informed me that the cancellation had not yet been loaded and that the R539 was for monthly data, which I did not understand because I had already cancelled the contract. Could you please assist me? Nosipho