The problem was which I first noticed last Thursday was that my phone wouldn't ring and just go right to voice mail. I don't fault Apple as it was not the hardware. My iPhone is a company phone so it's a little different. There are company apps on it although they had nothing to do with the trouble. But I can't go to an AT & T store to get it resolved. We have a place at work called the "iLab" for cell phones and laptops. So I had to wait until Monday to do it. So I had the phone reset to like when it was new. That didn't work. So they put in a "ticket" to IT. So later I spoke with IT (I do have a desk phone to use) and he told me all sorts of stuff about the account. No real help. So back to the "iLab". Then he gave me the name & number of the guy in charge of the company's mobile phones. He was helpful. I was on the phone with him for over 2 hours. He tried all sorts of things. After an hour he called up AT & T to speak to their tech too. So both of us were on the phone with him. She was on for another hour and tried all sorts of stuff. She did find things wrong with the account. But after all the changes and tryout is still kept going to voicemail. Well it was the end of the work day. So today I heard back from him and he remembered a similar problem and how it was fixed. A new SIM card. So he set one up for me, I went down to the "iLab", had it put in and it WORKED!!!! FINALLY! So that's what I've been through yesterday and today.