I have iPhone 3gs with iOS 4.2.1 installed (NOT JAIL BREAK SET, RUNNING WITH OFFICIAL APPLE iOS, NOT REFURBISHED SET) and in recent days its giving problem. It will be completing its 1 year soon.. Suddenly it is getting switched off frequently even though phone has cahrge of 50% some times even when it is 92-95% I need to switch it on again and it is taking some time. Not only particular application, it is switching off while checking mails, opening any games or any other applications. Those applications are worked fine and its warranty about to expire soon ---20 - 25 days. I have also tried to remove all the unwanted applications....still same issue... Also it is taking much time to charge it to 100%...any battery issue? Before the warranty expires, I have an option to replace it...our service provider will replace it with refurbished set.. can I go for that option..any suggestion/advice in this reagrd will be very helpful..