mobile under warranty but still not repairing it

Location/place: kanpur

Name of company/service: nokia

my mobile c5-03 is under warranty of company but still its service center is not making it by giving the reason that it is damaged due to liquid problem & company do not cover such things….
How so ever i didnt know how liquid problem prevails…….& company also didnt mention that they didnt cover such things in the booklet provided at the time of purchase