How do I make a successful Retrieve of Deleted Voicemail on iPhone?

To retrieve deleted voicemail on Iphone, you have to open the phone app, which will lead to a Voicemail tab, scroll down until Deleted Messages are found, which acts as a recycle bin for voicemails. You are able to re-add the voicemail to your inbox there. In case the voicemail is lost, then you can have your iPhone restored using a backup that you had created in the past. More sophisticated recovery applications can also scan the internal hard disk to recover deleted voicemail messages that have been deleted.