There is only one operator in the entire country who will change your postpaid plan without your consent and charge 6 times more and demand it.
That is reliance. Be aware of them. The worse operator of the country.
Get BSNL. It is far far far better in terms of service and offerings. Even if I pay more I have a satisfaction that I paid a PSU. Worst of the worst of the worst of the worst of the worst of the worst.