Airtel — Refunds

I have raised request to close my airtel xtream fibre account on 11th march, they told me to wait for 45 days to processed and within 45 days my money will re refunded I have waited till 6th May and send them email. They again filed the closing request as per 7th may and told me that earlier it was some technical error, again they told me to wait for 45 days. I have waited till 22nd june and one 22nd june they promised me to refund the amount within 7 to 10 working days. Today is 8th July, I sent them email, called them but no reply. Their customer helpline told me that we can't do anything. So In total its been 5 months that I am chasing them for my deserving amount of money. Its been mentally stressful.
I have all the proofs such as the first request screenshot from their app, emails conversation, phone recording with their customer's executives.