Airtel Broadband
No connection after a month and not refund deposit

I had applied for a braodband connection with Airtel. They were prompt in collecting my documents and initial connection/activation charge of Rs.500

After 2 weeks there was no action and i called the concerned person to check on the status. He mentioned that there was some technical glitch and not able to load the form into the system. This went on for 2 weeks. After repeated calls and requests they said its prcoessed now and gave a phone number. But again there was no action on the internet connection and again after 2 weeks of repeated calling they came back and said connection not possible because of non availabilty of pin for my area.

I feel they have done this intentionally and do not want to give a connection because i was regularly following them up daily to get my connection activated. They have not yet refunded the amount

please advice