Even though Uninor and Reliance GSM networks assures that the users can avail voice mail box number facility , they does not share any official voice mail box number.
So, you can ensure whether there is availability of voice mail facility in your network by calling toll free helpline number 198
Only few mobile networks like Airtel, Vodafone, BSNL has voice mail option for free.
By enabling voice mail option, the caller can leave you a small voice message for about 60 seconds , when your phone is switched off , not reachable, or busy with other calls.
So, if you don’t have voice mail box option in your mobile network, then you can have other option called call forwarding.
If you activate call forwarding, then the call will be redirected to other emergency number that you feed in the settings under certain conditions like phone switch off, not reachable and busy.
To enable or disable call forwarding in your mobile phone, view this procedure.
Call waiting :
Call waiting is a necessary option that every caller should enable in his phone.
If you activate call waiting option, you will get call incoming notification beep even if you are in another call. You can switch the call if the new incoming call is very urgent or priority.
To activate call waiting, view this procedure.
By default , call barring or blocking facility is disabled by your network provider. If you want to enable call barring, you have to make a special request to your network provider to activate it. Do not try it by yourself which may lead to PIN number and PUK code lock. To know more about call barring settings view this procedure.