I have my Thunderbolt for about a week. Twice so for it has changed my current location, Time Zone, on it's own. It switches to Sacramento, Ca(Pacific) I live near New Orleans,LA (Central). I cannot force it to change back. It will stay this way for 8 to 12 hours at a time. It has happened both time at my home. VZW tech support seems to be baffled. Any Help?