Karbonn K551 — Mobile got repaired within Warranty period

My Name is Ramaswamy. I brought a karbonn k551 on 08/02/2010. And soon the mobile was not working properly.
That mobile got repaired & entire circuit board having damage.
The mobile warranty is one year of the sale date. But its compleated only six months.
So i went back to karbonn service centre gave back my mobile with warranty bill xerox on 14/08/2010.
Still now they did not repaired back more than two weeks has passed and still there is no sign of my mobile getting repaired...
What should i do? Whom should i inform regarding this?
Is there any way to solve my problem?
Give me a solution...