This is a good one. Suddenly my galaxy s4 stopped receiving and sending calls. I could still receive texts and emails. My wife's Galaxy s5 worked fine. Went to ATT store (my provider), as I walked into store my phone began to work. Went home made one call then my phone quit making and receiving calls again. Next day went back to ATT store (phone working in store) and they told me the gentleman they just serviced had exactly the same problem, the same phone and they told me I should get a new phone. I decided to try a new sim card for $5.00 instead of purchasing a new phone. The new sim card did not work, inside home problems, outside worked fine be it a little slow connecting. So I went to Best Buy bought a new Samsung S3, worked fine until I got home, same thing inside no, outside yes. Now I know it is not the phone, something inside my home is blocking just my number/phone as my wife's (same ATT account) works fine. I shut off all electronics in home still my phone is not receiving or sending calls. My wife calls my phone an it goes to voicemail with my phone on and in my home. Anyone figures this one out has got to a genius.