More often than not, when I go to place a call, nothing happens. I go to my contacts list, click the green phone button, pick the number I want to call and nothing happens. It doesn't place the call right away. Sometimes it places the call instantly, sometimes it takes awhile. This is urgent, because if I'm in an emergency situation, I need to be able to rely on my phone and be able to place calls quickly. Why does this happen? How can I fix it?