Somehow, my IPhone 4s had a software upgrade, and it DELETED contacts. Anyone else have a problem with this???? UGH!
I had a thunderbolt before my IPhone, and my contacts were saved to the verizon back up assistant. They are now nowhere to be found!
If you were already using iOS 5 where you using the iCloud feature to back up your device? If so, you should be able to retrieve your contacts. If you just upgraded to iOS 5 where you backing up your device on your computer via iTunes? You were advised to complete a backup prior to proceeding with the software update...if you did so then a copy of your back up should be available in iTunes. Try looking at the following link to see if it helps:
If you did not do a backup and you were not using iCloud to do backups then you would need re-sync your contacts from another source...did you use a contact manager on your computer (such as Outlook)? If you did then you can retrieve your contacts from there. Try looking at this link to see if it helps. If it is not the correct one you can do a search on that site to find the article that better fits your needs.