Vodacom Early Cancellations

Early cancellation of cellphone contract paid for in full +-2months ago and yet still being invoiced for same cellphone. Numerous call as well as numerous staff - documents not received or who knows - emails sent numerous times and endless promises - however STILL BEING INVOICED. Stores are there to do the sales however any cancellations or other problems they seem to request that the call centers be contacted and this is pointless. Need to be credited accordingly ASAP. VODACOM USELESS IN ASSISTING WITH PROBLEMS!!!