Fastrack — fastrack sunglasses frame broke - after 2 month

Address:	682032
Website:	www.fastrack.in

The fasttrack sunglass i bought on jan 27th, 2018 which i use only while i drive car, safely handled and used in its string case. Today morning when i took it from case, noticed that its frame is broken. I am attaching the photo of my glass, its cover where i safely place when not in use and the warranty card.
From the way its broken its clearly evident that its broken by itself with no intervention externally.

I would like to hear from fastrack on what you advise to get me this replaced.