Several of my iPhone 4S apps that were previously deleted will not reload. I've tried all the tricks, buying again & such, but the app shows up with a blank greyed out button where the "install" or "buy" would be! Peapod, Shazam etc. not outdated apps & they work on other device such as iPad. Though they were purchased on the iPhone 3g they were not specific to device previously & they work on the other phones we have.