I have two Samsung Galaxy Centura phones from Wal-Mart with Straight Talk/TracFone. One works great between wifi and 3G. The other rarely recognizes the 3G, unless you turn the phone off/on. I've tried calling for support but all I get is the standard "call in to reprogram" which doesn't help. Also tried switching 3G/wifi on and off, but that only works sometimes. Both phones are used from the exact same area, but only one has this issue. Any suggestions?