I have had great voice and data coverage where I live for years and in the past couple months it has been horrible. I used to be able to make a call anywhere from my house, including the basement, and now I can't even make a call from my front porch sometimes. In zipcode 37110. My phone says it has 3 to 4 bars of service when I try to make a call but drops to 1 when I hit send and then just sits there and never even dials out, it just ends the call after a few seconds. What gives?