Shocking service yet again

I paid out my Cell C contract (the entire amount owing) in Jan 2015. I repeatedly begged that this cancellation be processed as I was going overseas. It wasn't and then eventually (after complaining) someone called Blanche Opperman from 'Escalated Queries' said that it was cancelled. My contract was converted to pay as you go but despite this I have just been charged in March!!!! How - when I cancel and pay out my contract in Jan (and don't go over my monthly allowance of minutes/ data) am I STILL paying. I am however not surprised. I have emailed Blanche 5 March and not heard a word back when I explicitly said to email me back and urgently process a refund before I get charged yet again for a contract which is not on pay as you go (and fully paid out). This is shocking and I would like someone to urgently address this (and, as I am still out of the country, EMAIL me the response).