INCORRECT BILLING

With the transfer from Autopage to Vodacom, and not my request, my billing amount has been changed without informing me. If I call Vodacom they say I must contact Autopage. Autopage just comes back with an answer that the case has been closed. My contract only expires in 2017 and is a data package. How do I get Vodacom to change my amount to the Autopage contract and get refund on the over billing.