I'm sorry to hear that you're having these issues.
Unfortunately, I'm not sure I'm able to perform troubleshooting beyond either removing the battery, or checking for updates through the system menu.
You might check with your carrier's repair center to see if you can show them where you have full bars, but aren't able to get a signal. They may be able to investigate into either their network or your phone itself to find the problem.
Hey, i have had my Samsung B3310 for half a year or so now and until recently have not found any problems. However, i am currently experiencing odd signal patterns; When my phone tells me i have full signal i infact have no signal, and vice versa. I suspected this was just a comical fluke at first, but that has been happening for 3 weeks or so now and i find myself actively seeking out areas that my phone tells me have no signal, as i cannot recieve texts or calls when i have 'full signal'. I'd just would like to know if any of you have encountered this problem before, or if you have heard of this occuring, and if so, should i be at all worried?