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).
Login iPlum portal https://my.iplum.com/.
Click Voicemail icon and select the user.
Click delete icon to delete voicemails.