cancellation not done

Good Morning, i called last week Thursday 13/07 to cancel my contract and put it back on pre paid, the gentleman who assisted confirmed that it was cancelled and we should receive a referance number (which i never got) today the upgrades department called for me to upgrade and i told the lady we had cancelled the contract - to which she said it has not been cancelled! also we keeping asking about an additional amount of R12.17 being added to the contract and no one knows what it is for! it has been like this for 2 years and i would like a refund. please can we have this issue sorted out as soon as possible!