Karbonn A15 — now phone is dead

Address: Patiala, Punjab

I purchase karbonn A15 3/12/12 khushi communication patiala after 3month problem in handset,hanged, late dialing, battery problem,I take it service centre [ singla communication patiala ] what after service the problems grow up in handset after three or four time service it is dead.
I write to company but not response from company after one month.