Galaxy m31s serious display problem

[Kiran123456789]

Hello every one, 2 days before i noticed a line on my m31s. I have done nothing in my phone not even charging. Just i wake up at morning i see lines through my display. Actually the out side of the screen not even had a scratch. Some thing happened on the inside of my screen and i dont know why.And today the lines had developed into pink and black colours on bottom of display. It is manufacturing defect. Phone is only 25 days old. What can i do. If i go to service centre will they replace my phone? What will be the reason for this and what parts of phone needs to be replaced for this. Please help....
Images:
https://postimg.cc/gallery/SyXbYwY