Idea Cellular — No network for month

I have been using idea number for 8 years now and one fine day suddenly it stopped working with no network service at all.
I tried resetting and connecting to customer care executives, but no helped, they said they can't fetch any details.
I visited Idea Store, and they are asking 5k to issue a new SIM with same number.
This number is linked to my bank accounts, and other places too, for which I am unable to access any of them as I am not getting OTP anymore.
This is very frustrating and feeling helpless now.