Damaged I phone X

I bought a new i phone x from cell c clearwater mall and the assistant explain to me about the 7 day out of box warranty were they replace the phone. After seven days i had a problem ( the phone not switching on) as i am staying 300km from the clearwater store i took it to my local store. They told me it wil be better to take it to the original store at clearwater mall. So i phoned cell c clearwater and spoked to Andrea who said that it is not her problem if my phone is broken, and she also told me she is going to put down the phone because she is busy and i am waisting her time. I am having 3 pinnacle unlimited contracts with cell c and this service is unacceptable.