Debit order processed even though no contract

On the 19th October I received a call offering me an upgrade, which I accepted. Two days later I changed my mind, and called to cancel the upgrade - I was told the cancellation was successful. <br> <br> Now, over a month later, I've had R150 upgrade fee debited from my account. I called to question it, and was told that the R150 is payable even if the contract is cancelled!<br> <br> I would appreciate a refund as soon as possible.