Airtel — airtel not returning my money

I had recharged my number ([protected]), with airtel's recharge plan of rs.399. I did the recharge from airtel website (https://www.airtel.in/prepaid-recharge). one time the recharge failed and the next time it went through, but airtel charged me twice for it and since then have not refunded my money. I have raised a complaint with then, and sent numerous bank statements, but still no refund.
Airtel complaint number: conrc[protected]
Conrc[protected].

My name: priyanka chatterjee
Email: [protected]@yahoo.com
Contact no.: [protected]