RETENTIONS DEPT NOT RESPONDING

I WANTED TO CANCEL MY MTN 3G ACCOUNT AND WAS TOLD TO GIVE 30DAYS NOTICE WHICH I DULY DID, MY ACCOUNT WAS MEANT TO BE CLOSED ON THE 21ST DECEMBER 2015 AND LO AND BEHOLD THEY DEBIT ME R125 IN JANUARY, I HAVE TRIED TO FIND OUT WHICH THIS IS FOR AND NO ONE IS RESPONDING I JUST KEEP GETTING TOLD IT IS WITH THE RETENTIONS DEPARTMENT.<br> <br> I EXPECT A FULL REFUND AS FAR AS I AM CONCERNED I DO NOT OWE MTN ANY MONEY.