Nokia Care not ready to repair 3 month old mobile handset

Location/place: New Delhi

Name of company/service: Nokia

Dear Sir,
I purchased a nokia 300 mobile phone on 31st of march 2012 from a valid dealer & on Bill with one year warranty & just after 3 month the unlock key of the phone stop working so its not possible to use phone when i went to nokia care at lajpat nagar they refused to repair & asking for charges to repair the phone, when i told them its in warranty they started misbehaving & return back my phone. then i insisted that u have to give me reason why not u are reapiring my phone they give me delivery note & giving reason that liquid found on key pad.
sir my phone’s key pad & all other buttons are working properly except unlock botton which is on screen & opens when we slide on screen its problem on the screen they are making completely fool of me.
Kindly Launch my complaint i have all the required documents.

Thanks
Sachin malhotra
Phone : 9312312060