Upgrade order executed without permission

My dad was recently phoned by a Vodacom call centre with an offer to upgrade his contract. He declined the offer as he wanted to physically go to a Vodacom store to select a new handset. We are currently sitting in a Vodacom outlet and have been informed that my dad’s contract was indeed upgraded; the status reflecting as complete. He can now only upgrade again at the end of 2019. The monthly installment was reduced, but this is not the outcome we wanted, as we are in need of a new handset. Clearly this contact centre was not listening to my father’s responses and therefore executed against our wishes.