We’ve already seen on how to activate or deactivate the missed call alert service which sends you an SMS informing you of people that tried calling you when you were unreachable:
I tried to call you at [time] on [date]. Please call back.
In some cases you may also want to get the missed call alert while you’re still on the network; that is, your phone will be on and reachable, but your callers will instead be notified that you’re not available, thus effectively blocking them.
This service may be useful in a couple of scenarios such as:
- for numbers that are primarily for making outgoing calls only
- when you want to block all calls but still retain the ability to make calls
- when you want to monitor people trying to call you without having to block them
Whatever your reasons may be, here’s how to go about enabling or disabling the service.
To Activate the Service
1. Go to your phone and dial the following activation code: **21*0722199199#
2. You should then get a response with the message Succeded.

To Deactivate the Service
1. Go to your phone and dial the following code: ##21#
2. You should then get a response with the message Succeeded.
How this Works
This service is part of Safaricom’s voicemail service and works through the call forwarding (divert) settings. The voicemail feature is therefore also activated and your callers, while they may not be able to reach you, will still get the option to leave you a voice message should they wish to.

When somebody calls a number that has this service activated they will be forwarded to the number 0722199199 that is inside the activation code. However, unlike the normal missed call alert divert that works on the condition that you’re actually unreachable here all calls are diverted to that number irrespective of your availability.

As such you can alternatively set this up as a call divert/forwarding setting in your phone. Just go to the Call Settings in your Phone settings and set all calls to forward to 0722199199. On Android phones this option may be named as Always forward.
Thankyou so much!!!
You’re most welcome!