Mtn
Debit orders deducted after cancellation

I cancelled my MTN data contract on 27 November 2013 and a reference number was given
I was told that the effective date was 27 December 2013 and that no further debit orders would therefore be deducted after this date

On 7 January 2014, R149 was deducted from my account

Several mails have been sent without any acknowledgement or response and I have tried to call numerous times without any luck.
I want to know how this will be rectified and when the money re-imbursed!