Disgusting

I was recently contacted by Vodacom to inform me I could upgrade. The amount provided to me that would be due after the upgrade, was agreed upon. I paid the additional upgrade fee last month, and my new instalment was due to be less than what I was paying, therefore I added insurance on the new device, which would have brought the amount due to roughly the same as what I was paying prior to the upgrade. However, I have received my new invoice totalling almost R400 more than my previous amount. Vodacom has not been helpful in assisting me at all and all they tell me is what my invoice is made up of. Either the consultant **** about the amounts during the recorded conversation for the upgrade/provided incorrect information, or I am being unfairly charged. I have always paid my instalments and to receive this disgusting level of service, is not on.