Instructions apply to iPhones runningiOS 10and later.
TapVoicemailin the bottom right corner.
If there aren’t any retrievable voicemails, you won’t see a Deleted Messages option.

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Tap the voicemail you want to recover.
TapUndeletebeneath the selected voicemail.
On some versions of the iOS, tap the red trash icon with a line through it.

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TapVoicemailin the top left corner to return to the main Visual Voicemail screen.
The voicemail you just retrieved will be there waiting for you.
ChooseClear Allin the top right corner.

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TapClear Allin the pop-up confirmation screen.
YourDeleted Voicemailsfolder is now empty, and you’ve got the option to’t recover anything that it contained.
FAQ
In most cases, you’ll need to contact your mobile carrier torecover deleted Android voicemails.
Unfortunately, once you delete voicemails onGoogle Voice, you won’t be able to recover them.