Nikon India — not replacing part under warranty

I had given my nikon d5200 in pune service center because of blurry viewfinder. They told me that my product is in warranty and diopter will be replaced under that, yesterday i got a call from service center and they told me that they can not fix this under warranty as there is internal damage, i asked them how i can damage the internal part of the camera if it was not dropped earlier by me and diopter is only used 2-3 times till now after listening this there answer was they are agreeing all this but they can not fix this under warranty.

This type o[censored]nprofessional reply is not expected from nikon service center.

Please help me on this asap.

Service req:pne-005078