Mr Price policy

Hi I'd like to have a clarity with Samsung and retailers who sell their products. I bought a Samsung A26 from Mr Price in Durban on the 13th of May 2025. The device works perfectly until the 19th of May it started overheating to an extend you wouldn't even put the device in an ear to answer the call. When I return to Mr Price the representetive told me that seven days return policy is over they cant exchange the device. I was told it will be sent to Samsung for repairs which will take up to 21days. But it was not clarified when do start counting the 21days period and I'm living with borrowed phone while I purchased a new phone. Please advice on what to do next cause the phone is essential in my work to communicate with.