Apple India — water damage issue

Address:

J-89, Rama Park Road, Mohan Garden, Uttam Nagar, New Delhi-59, New Delhi, Delhi, 110059

I bought an apple iphone x which is highly water resistant. But as i have used for once only there is no issue i found in my iphone but after few days i have seen some water marks inside of my iphone's back camera and after few hours i found a pink line on the display of my phone. I took it to apple service center and they checked the phone and said this can be fixed but it will cost you 55000 rupees to fix it. If it is water resistant then why it got damaged and why apple is not fixing it or replacing it.