You can press keys at any time in Voicemail. Just press 6 (next message) right after 7 (delete) and you will immediately hear the next message. You never have to listen to the announcement you can press keys like crazy. I think pressing 1 sometimes will skip certain announcements as well.
This feature can be added on future versions of VitalPBX, if you would like to add manually you can do it create a file under “/etc/asterisk/ombutel/” named as “voicemail__20-general-custom.conf” with the following content: