MTN does not respond to my cancellation request

From the 13th of March 2015 until now MTN is avoiding my request to cancel a data subscription. According to my knowledge I requested a month to month data service and MTN says it was a two year contract. All I am asking is that MTN supply me of proof that I indeed signed or the tape that I requested a Two year contract. Surely this is not an impossible request? After 8 emails and after three months I get evasive answers from MTN and in the meantime still have to pay R259 a month for an account that I am positive was suppose to be month to month.<br> Failure of their(Mtn) proof I demand credit From March and an immediate cancellation of the account. If there is indeed proof that I have requested a two year data contract I apologize and will honor the contract. The reference no: *** [#***]