rejection of replacement in warranty period

Location/place: bh 5 c , lpu, phagwara , jalandhar punjab pin144402

Name of company/service: Hewlett-Packard

sir i have purchase a laptop serial no 5CD1281VXC on jan14 2012. my battery is not working properly. i have registered complaint in hp customer care but after 15 days of ignorance and cheating me they finally told me that they will not replace my battery. sir my battery is still in warranty so how they do this to me???
strict action should be taken against such frauds and cheaters .
thanks