turn on suggestions
Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type.
The normal troubleshooting steps are Hard reset Restore from a backup via iTunes Restore as new Have you tried these steps? If you have and the problem is still there it must be a fault with the handset. As your phone as a 4S it must still be under warranty so take it to an Apple store and ask a Genius to check it over. If it is faulty they will repair it there and then. You could also ask Vodafone to repair it but that would take a lot longer.
