Hey, I work for T-Mobile as a technician (nothing special, for now).
The visual voicemail app is for the free visual voicemail service from T-Mobile. It lets you listen to voicemails from a GUI instead of a calling interface. The premium feature is "voicemail to text".
If you've reinstalled the app, cleared your own cache, etc, then call customer care and let them troubleshoot. You could be missing an account feature or two required for the setup.
For phones that have OEM Visual Voicemail (iPhones, any android with a "voicemail" tab), the app is good for setup, but otherwise is not needed. As long as the account features are good and your phone is in no position to have any bugs around interaction with carrier features, then it should work without a fuss.
---------- Post added at 08:31 PM ---------- Previous post was at 08:28 PM ----------
We have a system and method for dealing with issues where all of the above is correct and done and it's some kind of exception (non-TMO phone we haven't troubleshot this far before), it just takes a few days or longer to interact with the engineers and developers. We can't take logs or reports of any kind, but the information we need is brutally specific.
---------- Post added at 08:31 PM ---------- Previous post was at 08:31 PM ----------
We have a system and method for dealing with issues where all of the above is correct and done and it's some kind of exception (non-TMO phone we haven't troubleshot this far before), it just takes a few days or longer to interact with the engineers and developers. We can't take logs or reports of any kind, but the information we need is brutally specific.