You can set Visual Voicemail to permanently delete messages from the Trash folder after a specific number of days:
1. Open Voicemail settings. (Press your device's Menu button and then Settings in your voicemail Inbox).
2. Select Delete Messages. A screen appears with options for the number of days deleted messages may stay in your Trash folder, after which they are deleted permanently. The options are:
● After 30 days
● After 10 days
● Immediately
● Never
3. Select one of four options above or tap Cancel. You will return to the Settings page.