Complaint to Vodacom

Livered, had a contract where I received shared data for 2 phones. After 24 months Vodacom upgraded without informing me and now I am receiving data and airtime. Who gives Vodacom the right to upgrade without my consent. If no consent was given to upgrade, no phone call from them to inform or a new contract offer then im not interested and do not want airtime and data. I need shared data for 2 phones. I am with Vodacom for many years and this is what they do. Not a happy customer at all. This complaint is for my aunt thats over 60 years old and she is in tears with this whole situation because even the branch told her there is nothing they can for for her.