Subscribed my mother to a service without consent.

My mothers airtime kept on disappearing for no reason, called Vodacom they said she was subscribed to a Vodacom Live Service. How is it possible for my blind mother to subscribe to a service she has no access to the only thing she ever does on her phone is use the talk back to whatsapp other people. She is also always on WiFi so no way airtime could disappear besides a **** that someone subscribed her to a service she had no way of subscribing to. I would like to have her R21 refunded to her since its unfair what happened.