IPhone :: 3GS Switches Off After About 3 Minutes Use

Since January I have had srious problems with my Iphone 3GS. Without any warning the screen goes blank, but when I look closely there is a broad darker band running down the whole length of the screen. I am only able to take a maximum of 2-3 photos and if I try to connect to the web 3 minutes usage time is the maximum. I then connect the phone (if I am able) to a power supply and after the apple logo appears, it is followed by a battery symbol showing almost zero power. This is shortly followed by the audible sound that the phone makes as it picks up the power and the battery symnbol immediately reverts back to the status it was before the 'shutdown', this morning it was 83%. Also when i switch on the phone, the battery symbolin the top right hand corner is not green, it is white. I have taken the phone back to a brand-new phone & shut down location services, push notifications, backlight etc...but this awful situation continues!!

As my phone is not on contract and is nearly 2 and a half years old I feel that Apple have me by the proverbial 'short and curlies'. My iPhone is used on a daily basis and I must admit that I am lost without the reliabilty of it's functions. I also feel that for the cost of the phone, the battery should surely have a longer life!

I would be willing to have the battery renewed if I thought that it was failing, but is it, or habe Apple dropped a clanger and it is a software fault that they are unwillinmg to disclose, due to the backlash from it's customer base and the possible loss of future sales. As I was in the market for a desktop this summer, that is a substansial lossin sales from this one customer alone!

Info:iPhone 3GS, iOS 5.1