Huawei Band 6 Bracelet: Scratched Case = No Warranty, High Repair Costs

In all honesty, my recent purchase of a Huawei Band 6 bracelet has left me very unhappy. Shortly after purchasing the device, it began to turn on and off by itself and the message content became unreadable and texts disappeared. I contacted customer service within the warranty period, but was told that the device was not covered under warranty due to scratches on the case. I have a few questions regarding this experience. Firstly, how can a small scratch on the case affect the operating system and therefore not be covered by the warranty? Secondly, when the price of the device is 700 TL, how can the repair fee be increased to 1400 TL? This is my first time purchasing a Huawei device and I must say, it will also be my last.