Device : IPhone 6S+ Network : TMobile iOS Version : 9.3.3 (13G12 ) - But problem has existed much prior to this! I just don't get any Voice-Mail notifications, and under the 0_0 Voicemail tab it says ' Unknown ' with a 0:00 timer. However, as soon as I swap my SIM in to the Galaxy S7 / Note 5 etc.. the Visual Voice Mail icon lights up! The only time I'll get VM notifications is if I reboot my iPhone. Resolutions attempted: 1 - Spoke with Apple Tech Support. They couldn't figure out what's up so asked me to restore as 'new device' 2 - Had TMobile reset my VM settings, in vain. 3 - Restored from back-up, in vain. Is anyone else facing a similar issue with their VM and/or is setting up as a new device the only fix ? Thanks!