Karbonn Mobiles — regarding servicing of mobile under warranty period

I gave my karbonn mobile model A99 having display problem six months back to a service center in mangalore (deepa compartment, near empire mall) and they are not returning my mobile.Their service is very bad as they keep postponing the day to return my mobile. I even went their and talked to them personally but it waste of time. I am complaining as this is the only last thing i can do. Claiming my rights, due to not available of my online net banking i m not able to get money so, I kindly request you to look into the matter seriously and to do the need full at the earliest possible way. Thanking you.