Have you tried to restore your iphone
from a previous backup
To restore information from a backup, use one of the following methods after connecting your iOS device to the computer with which you normally sync:
Right-click (or Control-click) the device and choose Restore from Backup
If you have a new phone, you can connect to iTunes and it will prompt to restore from your backup.
If that does not work lets try to restore the software on the iphone.
Verify that you are using the latest version of iTunes before attempting to update.
Connect your device to your computer.
Select your iPhone, iPad, or iPod touch when it appears in iTunes under Devices.
Select the Summary tab.
Select the Restore option.
When prompted to back up your settings before restoring, select the Back Up option (see in the image below). If you have just backed up the device, it is not necessary to create another.
Select the Restore option when iTunes prompts you (as long as you've backed up, you should not have to worry about restoring your iOS device).
When the restore process has completed, the device restarts and displays the Apple logo while starting up:
After a restore, the iOS device displays the "Connect to iTunes" screen. For updating to iOS 5 or later, follow the steps in the iOS Setup Assistant. For earlier versions of iOS, keep your device connected until the "Connect to iTunes" screen goes away or you see "iPhone is activated."
The final step is to restore your device from a previous backup.