Airtel — Airtel Broadband Refund after taking 3 months advance and sharing false information

Hi,
I got a new connection from Airtel broadband that promised as per advertisement and salesperson of 40 mbps speed. Post connection field engineer informed that max speed supported in my area was 14 mpbs. As this speed was not sufficient I asked for immediate disconnect and refund. I had got connection in first week of June and laid 3 months advance rental of Rs 3532 and my registered number is [protected]. It has been almost a month now and I have not got my refund yet. First they give connection with false information and then they harass customer to refund money. Kindly look into this from your end