Cellphone purchase

I am not happy with Makro Alberton. My husband bought a phone 3months back a hauwei nova y70.It gave us problem from the first month then last week Sunday it completely went off.So on Monday he went in store and they told him to take the phone himself to vodacom repairs.so it could be faster. Hence they needed to check if it's factory fault or what. He did that and repair called him to come collect today only to find out that it's factory fault. The phone is fixed but we longer want it, the slip states that it's up to the customer if they want exchange, refund or keep the phone. He then went back to the shop but the manager Keith refused to exchange the phone even when we had prove that it was factory fault. He gave me attitude on the phone as well.