Hey shumanak, Im really sorry about that. It shouldn't take that long!! I would call the number again to make sure everything is set up correctly on your account and with your voicemail. T-Mobile DIGITS | Unsubscribe for Public Beta
Just to make sure, you are not receiving the voicemail notification on your primary phone. Correct? If you haven't already, please powercycle your device by leaving it off for about 30 seconds and test it again. Sorry again you are having issues with DIGITS.
Just to let you know that opting out of the beta, really only takes you off future notifications, surveys and mails about the beta. During the beta we added your number to have access to the new functionality, but that functionality is part of the core network. While we can remove access to DIGITS apps, we elected to continue to provide access since being able to access the functionality should have no impact on other core network operations.
Sorry to hear that you're still having issues with voicemail notifications. It sounds like there might be another issue happening here and it would be great if you're still having this issue if we can get more details and then have a bug filed so that it can be investigated.