Xiaomi India — second sim slot is not working when dual sims are inserted

The second sim slot of my redmi note 5 is not working when two sim's are inserted. The complaint is from the very first day i have bought the phone that is from 10/7/2018. I have reached the mobile store from where the phone was bought and i was informed that it is the trouble of the sim so i took a new sim but even after that the problem persists. When i took the phone to redmi service centre in kottayam i was told that my phone have liquid damage and i should pay for it but the problem with my phone is from the day i brought it and it is not exposed to any such situations to get liquid damage. I want a favourable solution.