Terrible service from store and HO

A consultant at the Tygervalley store sold my mother an adapter that was not needed after my mother informed her that I already have a charger. She insisted that the charger I have would not work. This is not true. I visited the store to get a refund which they refused to do and told me I need to exchange the item for something in store. I do not want anything from the store, I want the money we spent back as the original Apple adapter is half the price of the one sold to us. The manager refused to come out from the back office to speak to me and the consultant Tyler told me to contact head office. Which I did, only to be told that they can't assist and we need to speak to the store manager. I have not received a response via email yet after informing them that the store manager refused to speak to me. I really don't care if the stores are franchise owned, it is still a Vodacom store. I impatiently await your response.