SA Post Office
Cancellation of a postal order not done

I have sent a postal order to the dep of education last year November, via normal mail. The postal order was lost and never reached the destination, From the beginning of January 2013. i have given the receipt to Bluff post office to cancel the postal order, to date they have advised me they cant process the cancelation on their new system. I want my money back and the postal order cancelled, how hard can this be, its taking 4 months. Please assist the staff of bluff post office to cancel the postal order and give me my money back.