Cancelling of contract and monthly billing

Firstly, the contract I hold with MTN expired on 08 June 2017 and no one contacted me to confirm that from July onward I would be billed on a month-by-month basis. Apparently this common practice so I accepted this and requested that the contract be cancelled. I was advised by MTN to contact them again on 09 Aug 2017 to cancel the contract which I did (even though this meant I paid for another month of a contract I was no longer using).

Then, on 14 August I received an email from the retention department of MTN saying that " cell phone number X will be permanently cancelled on the 2017-08-26 per 30 days notice". HOWEVER... I see on my bank statements I have been billed again on 07 September 2017 for the normal amount of R269.00... This is unacceptable and I now would like MTN to reimburse me the above mentioned amount and assure me that the contract is indeed cancelled.

The reference I number I received from the retention department was: ********** 5; while the original reference was: # ********** 5.

Caroline