Redmi — redmi 4a

Sir i bought redmi 4a then on the very next day i noticed that its flashlight was not working. I went to redmi service centre. After checking my mobile they told me that the ic on my motherboard are damaged and they need to replace the motherboard. But they told me that i will have to pay rs4500 for it because the motherboard dies not comes in redmi warranty... I just used that mobile for only one day... What can i do... Please tell me... Whether motherboard comes under warranty or not