how can I retrieve a lost voicemail that was saved

[EliNaz]

I had a voicemail from my late mother saved to my phone.  I always diligently resaved it every week or so to be sure I didn't lose it.  I went into voicemail today and it, along with two other messages, are gone.  Help!

[NFtoBC]

AKAIK, there is no means to retrieve voicemail messages which have been deleted from the system.