restoring voicemail from backup

I am not sure if I have an actual back up of the device or if I just backed storage on icloud (not sure if there is a difference)

Anyways I am trying to recover voicemails that were from the iphone that I reset. Before doing a factory reset, it asked about backing everything up to icloud which I clicked yes.

Now when I have since logged back into icloud there are only a few things on there.

What I want to know is if there is a way to recover the voicemails that were on the phone? Or are they gone for good?

Please advise