You can activate/de-activate diversions to your Voicemail in the following ways:
Online at My Vodafone
Using Vodafone short dial codes (this method isn't available whilst overseas)
Divert calls on no answer, when unreachable or on another call.
Divert all calls to Voicemail
Deactivate Diversions
Voicemail Notification
You can choose to be alerted of new Voicemail messages in either of the following ways:
TXT Alert
You'll receive a TXT for each new Voicemail message advising you to call 121 to listen to your message
Ring Alert
You'll receive an incoming call for each new Voicemail message and once answered your messages will be automatically played back to you
Note: To switch between TXT Alert and Ring Alert simply dial the activation short dial code as per the above instructions.