My voicemail is essentially useless.
I have an iphone 11 pro on IOS 16.2. I don't think this has anything to do with the phone and I'll tell you why.
I see when I miss a call.
I never have a voicemail notification despite people telling me that they left me a voicemail. I even left myself a voicemail and it doesn't exist.
When I call my voicemail and enter my password, I can listen to 1 saved voicemail that I have, but there's never anything new. Again, despite the fact that I just left myself a voicemail.
I have a custom greeting. It plays back from my phone app, but when I call myself (from another phone) and get my voicemail, it's the default generic greeting.
One of the troubleshooting options I've seen is to check call forwarding. When I go into my settings, call forwarding isn't even an option.