iPlum App
Open iPlum app and go to Voicemail screen.
Delete single voicemail: Swipe left and delete (iOS & Android).
Delete multiple voicemails: Click “Edit” and delete all (iOS). Long press any voicemail to show the multiple delete option (Android).
iPlum Portal
Login iPlum portal https://my.iplum.com/.
Click Voicemail icon and select the user.
Click delete icon to delete voicemails.
Helpful links:
How to change voicemail settings?
How to create custom or professional voicemail greetings for iPlum?
How to update for enhanced voicemail with bigger storage and voicemail transcriptions?