Incorrectly billed after upgrade

I upgraded my contract on ********** 506 as i was due for an upgrade, i did the application online and no where online nor a call from someone stated that i will still pay for the old device until the old contract expires. I am now being billed for the old device and i dont think its fair as i was not made aware of this because if i was aware then i would have waited until the term completed then upgraded. Vodacom i want my money back for the two months that you have debited me for the device and fix your system so that i get billed correctly from December. I have had so many problems with you and i honestly dont think its funny how you treat your "So called customers".

Contact me on ********** 951