I just switched from a DX to a Thunderbolt. 4g works great but if I move to an area with no 4g or if I use the "Network" app to switch to "CDMA auto" I have no internet at all. My buddy right next to me gets 3g when he goes out of 4g range or if he uses that app. What will I need to do to get 3g fixed on my account? Update: I should add that I bought this used and had Verizon give me a sim card. Maybe I need to hard reset the phone?