Hey, I've had this iPhone 3G since February of 2009 and its been great, never dropped it, kept it in a case and etc. But the battery life has been bad, I'm on T-Mobile's network. My problem is, I calibrated the battery 4 times this week and still this happens, the phone will die, it wont turn on, but after I plug it in, it will say I have 33% left, sometimes it varies and its never constant. It never stays at the red area and charges, it just goes up to the green part and continues charging. Why is it doing this? I want to find out why and have it serviced if there is something wrong. Also if there's no fix to it how can I exchange it in the AppleStore? Considering for one, it's jailbroken and two I don't know when the original owner bought the phone. I bought this phone from a T-Mobile merchant that sells them unlock. Which was quite expensive, so I'm just wondering if there's a way for the AppleStore to know when I purchased this phone to see if it's under warranty or not.