I typically screen my unknown incoming calls to my voice mail box. If they leave voicemail I only have to listen a second before I delete. Today I discovered that wasn't working and I could find no way to fix it. I went to my provider to iron it out. Though I had their sim loaded and had provided the new device info online it wasn't actually activated. They could not explain why it wasn't activated or the mystery of working phone, text, email etc service I've had since I put the Ultra online. Everything worked except my voice mail box. A bit weird and I think it was their bad. The no service BS was a bit difficult to accept as the culprit.