Telkom ***** warrant and technical department

Telkom refuses to repair my phone. First they tell me that my phone has scratches therefore it’s the cause of it freezing. My phone was 2 months old when I first took it. The screen is turning yellow and it’s getting bad and now the phone is freezing. My phone is a Huawei p20lite. They refuse to give me a proper report of what is happening to my phone and it has been there to 2 months. I was told that the phone needs a new motherboard and new screen but I must pay for it. I asked why they said my warranty is off because of scratches. Someone please help. I have all the details of the managers who assisted me.