one thing to check may be your settings. make sure that call screening is not on under your setting menu. this could prevent you from receiving calls from anyone not saved in your phonebook. when you try and call out, do you hear 3 beeps, and then it hangs up?? if so, then it might be a phone that was reported lost or stolen, in which case get your money back, cuz its pretty much useless. good luck!
That's good to know bewcause I have this stashed away some where and I have been wanting to donate it to the women's shelters, but I always had that problem. By the way, http://www.wirelessfundraiser.com/ is a great place to pass off your ols phones to the disenfranchised.