Samsung Mobiles - Rejecting brand new mobile replacement which came with hardware issues

I have purchased brand new mobile Samsung A** on May *nd **** and noticed that sensors are not working. Off late I came to know that sensors problem is due to hardware issue in manufacturing defect. Reached out authorized service centre at Phoenix mall Chennai to sort it out. The staff said that only hardware issue will be fixed and can't replace with the new device and informed me to contact customer care until we will not proceed further with mobile service. Customer care people are denying to replace the device stating it should be done with ** days of purchase. I am not aware that the model has such sensors as it is new in the market. Customer care informed me that they will fix only the hardware issue that caused during manufacturing. When informed the customer care regarding the same they came up with a new story saying that the mobile phone has a water lock and it will cost Rs. **,*** and will not cover under warranty. The mobile is brand new and used with almost care. They also said water lock might be due to sweating. I request you to please take the issue further and assist me in getting my mobile replaced with a new device.