Where do my voicemails go?

[Kanishka]

People will call and leave voicemails.
But after a few days, when I go to replay the voicemails they are missing?
how do I stop them from disappearing from my visual voicemail?

 

[Laura Knotek]

How many do you have saved? The old ones might be getting deleted if your voicemail box is full.
Sent from my Nokia Lumia 920 using Tapatalk

 

[fpostrow]

They go to the same place that all those celebrity nude pics went. The NSA.

 

[Kanishka]

i don't have any saved but i didn't actively delete them.
I show 0 vm's in my visual voicemail, and so I am wondering why they were automatically removed.
How do I set how many VM's i can see?