Replacement Policy for Liquid Damaged Samsung S7

Hi, I recently bought a Samsung galaxy S7 phone and was travelling to Europe the same day I bought it, 3rd June. After about a week the phone blacked out and stopped working but started working with some minor problems after 10 days.. But when I came back to delhi on 29th of june the touch screen stopped responding. I took the phone to the service centre and after checking it they say that due to liquid damage the phone has stopped working and refused to repair or exchange it under warranty. What should be done in such a situation because the repair cost is 40,000 INR almost as good as a new piece. But my main concern here is how a IP68 rated phone be liquid damage without any proper exposure to water except the general atmospheric moisture and why does the warranty get void in such a case if the company is widely advertising it as a water resistant phone?
Please help!