I went to Knoxville, TN for Thanksgiving today and brought my 4s with me and it's getting 2 bars average. Is it supposed to still get service? Before when I made calls it would fail, but now it calls American Roaming. It's a Verizon phone with an old SIM card, but it still gets a few bars when I take the SIM card out. Anyone know why? Verizon's 3g networks shut down a while ago.