Xiaomi India — MI band 4

Hii, my name is Udit
I had purchased a mi band 4, for almost 4_5 months ago, after 3 months, I was getting some problems in it, then I had gone to mi service center, to replace it, but they are refusing to replace it, because there are some scratches in it, as I use it 24×7, so it got some scratches, what is my fault in it, why I'm not getting proper service?
I request you, to please replace it .

Thanku