upgrade on false grounds

Vodacom sales rep called for an upgrade. Upgrade was accepted with Vodacom however, the sales rep failed to inform me that I will be paying for 2 phones and not one! I asked specifically how much will I now be paying and she confirmed that it would be the new installment, my bill however does not reflect as so. According to Vodacom, because my contract had not yet expired, it had a few more months before expiry, I had to pay for both the old and the new upgrade. I did not specifically ask for the upgrade, I was offered it, the sales rep SHOULD have clarified that I would be paying for 2 phones, this info would have prevented me from taking the upgrade at that time. I AM UTTERLY DISGUSTED by this level of service, I have never experienced this before and I certainly do not believe that Vodacom has acted in the clients best interest. I moved to Vodacom from years with CellC and funny enough, Cell C service has drastically improved and streamlined. Maybe this was the wrong service provider choice.