Godrej Refrigerator claims money on warranty period

I have purchased a refrigerator from Godrej company, on year 2008, which have 10 years warranty in rust free door. But already it become rust. I made complain to the customer care, and resived complain ID – K1309337822, on the date 13-9-2014, at 4.30PM. Now they answer me a bill around 1500, against, re colour of the door. How they could claim this amount in warranty period. I need justice.