Den Networks — Refund of Money

My name is Nishant Sethi, existing user of DEN Broadband with Username 'NISHANT5430'
I was facing internet connectivity issues with DEN on daily basis which was impacting my official work. I have now purchased a new Airtel Broadband Connection and requested DEN for disconnection of services and refund of money. They have denied to refund the money.
When I am not interested to use the services, why would my money not be refunded?

Please help in refunding amount of Rs 1000/-