I never had an issue with visual voicemail in the past till I went to set it up on my new galaxy s21 ultra. I kept getting a notice that said something like "being used on another account". This shouldn’t be because I’m using the same sim card that was in my old phone. As much as they tried, T-mobile help couldn’t solve my issue, which I read was an ongoing one for years. So I uninstalled the T-mobile VV app, and installed the metro by T-mobile VV app. It’s exactly the same app, the icon is also the Sam. BUT IT WORKED. So if you’re having an issue, forget calling tmo support. Just uninstall tmo VV, and install metro VV.