Audacity on your computer. After you have installed Audacity on your system, open the program and click on "Edit" on the menu bar.
Next, go to "Preferences" and then, "Recording." Now, tick the box by Software Playthrough. You will need a mini to mini cable. Connect one end of the mini cable into your smartphone and the other end into your computer’s microphone jack. Press the "Record" button on Audacity and then play your voice mail recording. When your voice mail recording ends, press the "Stop" button on Audacity. Click the "File" menu link, and select "Export" to save the recording as a MP3 audio file.