INCORRECT BILLING AND NO ONE WANTS TO TAKE ASSIST

I initially took contract with Vodacom in Sep'13 and unfortunately my phone was ****** in Nov'14, in Jan'15 I did premature upgrade. The handset bill for the initial contract was suppose to expire in Sep'15 (24months)but to date I'm still being billed. I phoned call centre, retentions and cancellations, upgrade dept. and I even went to a vodashop at Vodaworld and no one seems to care to assist me.<br> <br> I logged a call on the 26th December and my call is still open. My call reference numbers are: *** logged on the 26/12/15 and S3-GKN2O-OE4CL logged on the 15/01/16. I'm told they cannot access my account as I've been billed on their new system and they cannot access my records. I've been overbilled for 4months. Its ironic that if a customer doesn't pay, you line will be soft logged without any explanation or understanding yet I'm expected to continue to pay Vodacom and understand. I've had enough of your poor service. I need this mess to be resolved before end of the month and I demand a new invoice with all my credits and a free month for all the hassles you've costed me.