Samsung Mobile - Phone damaged in rain after servicing by authorized service centre

My * month old samsung galaxy S** phone display got damaged and i repaired it paying from my pocket. One week after the service, phone was in my pocket and got wet during rain and entire phone is damaged now. Before the screen replacement, the phone got wet numerous times and there was no issues. Now after service, suddenly water resistant property has vanished. Customer care people and service centre people are denying my claims but at the same time they dont know how water seeped into the phone and they cannot replace or repair my phone under warranty. They are charging Rs ***** for this repair which is unacceptable. The phone was ruined by them and i need a replacement now.