Airtel — paid for broadband connection but didn't get the installation done

I have paid 7780 to airtel broadband for new connection at my place, first they said it will take 48hrs for installation but its being 5 days no one came for the installation. Even after calling several times they giving false promises that it will be done in next few hours. I have asked for refund, after this much harassment they are saying that i need to call them again after 2 days to get a refund