Not sure if the DND facility provided by mobile operators still functions.
I have a Airtel number. Even though I have subscribed to the DND facility, I get numerous annoying calls from various banks.
At first I thought if DND settings were overridden, hence I again tried to set the DND and got a SMS stating that DND is still setup.
Not sure what more can be done to get rid of this pesk operators without ditching the mobile number:(