In the T-Mobile Visual Voicemail app, for example, tap the three-dot menu at the top right and then choose "Settings." In the Greetings & Pin section, you can tap the default greeting and record a new one.
Along with having my greeting screen frozen I was also not receiving any indication that a call was coming in...no ring, no vibrate, no visual indication on the phone at all. All calls were going directly to voicemail and the greeting was some funky message...maybe it was the default although custom was checkmarked. I also tried resetting, turning off WiFi, checking Do Not Disturb. Dec 3, 2015 6:13 AM Reply Helpful (2) User profile for user: susan from morro bay susan from morro bay Jan 6, 2016 3:57 PM in response to tar722 In response to tar722

Go to menu, and click on messages. At the bottom of the screen, it should say options. Click on options. You should see a list of options come up on the screen. Click on the one that says voicemail. When you click on voicemail, it should call the automated voicemail. You should hear an automated voice giving you options. When you hear personal options, press the number that the automated voice said was for personal options. The automated voice should then list some personal options. When you hear `greetings,` press the number that the automated voice said was for greetings. The automated voice should list some greetings. When you hear `personal greetings,` press the number that the voice said was for personal greetings. Follow the automated directions from there.
You will be asked to delete your current Voicemail greeting. Click on the ‘Yes’ button that appears on the screen if you want to remove that. You can save your new recorded Voicemail greeting or can use the default recorded option. Wait and hear the new Voicemail greeting message that the instructions speak out. If you want to keep that recording as your Voicemail greeting, then save it. Or you can re-record the message to get a different greeting.