There are several methods to manage your voicemail, via the 3CX Windows Phone or your mobile, one of the easiest ways is using your desk phone.
You can manage your Voicemail using any Desk Phone by dialing “998” (This may vary on your configuration). A voice menu system will announce options and allow you to dial numbers to access and manage those options. After you enter your Personal Identification Number (PIN), the initial options you are presented with are the following:
Dial * to play your messages
Dial “9” to go to options
Dial pound “#” to exit
Dial “9” for options. The following are the options announced by the voicemail system. Dial their numbers to change and update these features:
Dialling “1” allows you to change your profile status.
Dialling “3” allows you to dial a number.
Dialling “4” allows you to delete all read messages.
Dialling “5” allows you change your self-identification message.
Dialling “6” allows you to play mailbox information.
Dialling “7” allows you change your voice mail PIN number.
Dialling “8” allows you to change your greeting message.
Dialling “9” allows you to restart the voice menu prompts.
Ref: http://www.3cx.com/blog/voip-howto/managing-voicemail/
