Increase in monthly Invoice amount

Hi,

I have been on the phone for the last 3 days trying to resolve an issue with my invoice. In November last year Vodacom decided to increase my monthly amount without any notice without any reason. This is not what contract amount I agreed to and I am yet to get a call back.

Each time I contact the call centre I speak with a new agent and explain the story. At the end of the conversation each agent has said that they will chat to their supervisor and call me back. I am yet to recieve any call.

Please could someone contact me on **********