Airtel - Not getting refund of my Airtel Broadband cancellation

On **th November, the airtel executive came and they said I am eligible for airtel fibre connection. Then I registered for it and I did payment through the link came from airtel of ****/-. But at same day when technician came for connection he said in my area ther is no previous connection so they can't give me connection. So they cancelled my order of airtel fiber on same day that is **th November **** and said they will refund my money in * days. But today ** day have passed but there is no clue of my refund. I tried by calling on Airtel Helpline they said there senior will contact me but no one contacted me. I tried calling *-* time they said same thing. Then I mailed them on ***@in.airtel.com and they are saying my application id is invalid. I have proof of my application id and registration but they are still foolish around and not refunding my money.