Airtel — Change my prepaid to postpaid without my proper concent

Address:	Assam
Website:	Airtel thanks app

I am searching for prepaid to postpaid, l submitted a request they told me that someone will contact you for kyc and other details but they changed it without my proper concent
I am searching as I am going to Jammu where prepaid is not working, I also have nearly 2500/- in my prepaid account, now they are telling that it will not work in Jammu as I did it from app, customer care told me to contact at Airtel store and in store they said nothing is possible as I did it from app and only 600/- from my prepaid account will be adjusted in six months
If there is difference between app/ online and store then why they kept app and online, they had to shut it then people will go to store, earlier also l faced some other problem with Airtel
Only thing is that I want my money back and my phone again in prepaid mode with my full balance money