Service centre not delivering phone on said date

Location/place: new delhi

Name of company/service: karbonn

I had given a Karbonn A15 for repair in Cell Service Customer Care Karbonn,Tughlaqabad(Contact No.9350095009),Delhi on 28/01/2013.They said that it will take a maximum of 15 days to repair.But today is 25/02/2013 and the phone is still in repairing stage, whereas when I called Karbonn Customer Care many days back, they said that it will be done by 18/02/2013. But its still not repaired.

Karbonn Customer Care No. 1800 102 4660.

Kindly answer my problem and please refund the whole money as soon as possible