new phone malfunction/ bad service pick and pay fourways mall

On Tuesday 27 September 2022 me and my niece went to Pick and Pay Fourways mall to buy a phone. when we got there my niece chose a phone that she liked and she was assisted by Olebogeng, whom she explain partially about the phone. then when she was asked if the phone has a sim lock since its a dual phone, she then rep**** with " I don't know, I'm not sure" my question is how do you put someone who doesn't know anything about phones, nor who cant make an effort to get help from colleagues, who probably know about the product or item sold at your store. Long story short, the phone has 2 years guarantee... it doesn't even have 48 hours been bough already my niece is getting problems from the phone itself. When she approaches them for a refund they telling her that they wont refund her. Is this the service we going to get from the big store like this, when we asked for a the store manager he was nowhere to found...then someone from the store told my niece that the store manager is around. Why become a store manager and run away from your responsibility of offering good customer service. really bad service and incompetency from Pick and pay Fourways mall.