IOS 7, enable to setup personal hot spot After Updating latest version of iOS 7. I am not able to setup personal hot spot in my iPhone 4.

I use BSNL (India) carrier. I was told by the carrier that the problem is an issue with the iPhone update.

I use BSNL for 7 years with a 3G data plan. Until now, I have not had any hot spot related issues but after updating to the latest version of iOS 7 this problem began.

How can I solve this problem? Any hints or suggestions are most welcome.
setting- cellular- cellular data network.
Cellular data
apn: test
username: test
password: 12345678
Personal hotspot
apn: test
username: test
password: 123456789


have good day