Airtel — Airtel Broadband Fiber connection refund not received after cancellation and multiple requests

Airtel owes me a balance of 373 rupees on an account that I have closed. Chasing Airtel for 2 months after cancellation of connection. Refund still not received.

May 7th Cancelled my account and settled my bill via netbanking
May 11th Amount got paid again accidentally from BillPay which I had registered with my bank
Jun 14th Called airtel to request refund. Was told money will be dispatched by cheque to my location and I will receive the refund within 45 days from date of cancellation. Was asked to wait 2 more weeks.
Jun 28th Have not received refund yet. Called airtel and made complaint again. Customer service guy asked me to wait another 45 days. Got annoyed and cut the call.
Jun 29th Called again to customer service. Knowledgeable customer service representative looked into it and escalated the request and said I will receive cheque with 2 weeks. Service request registered.
Jul 23rd Not received the refund still. Called into customer service again. Was told refund not processed. Was told they will escalate to supervisor. Then they come back to me and say supervisor is not available. And saying they will place another service request.

I am waiting for a refund of 373 rupees for 2.5 months since cancellation of account. Airtel is wasting my time & effort. Such a shame that one of the top mobile service providers in India is behaving like this.