Have you ever met such annoying thing on your iPhone contacts like below?
Example 1: After I updated my iPhone to iOS 7, my contacts have been disappearing and then after about 10 minutes they will reappear. This has happened multiple times.
Example 2: lost my contacts on iPhone! This just happened to me as well. If your customer's are experiencing this issue, it is obviously a known issue. Backing up your contact list is pretty useless if your contacts have already been erased. I tried to access my messages and then all of a sudden my phone started moving slow and then my contacts were all gone. I did nothing different than I usually do.
If these things happen to you, what will you do? Ask your friend send their number to you? Actually, you can get them back! Just try the ways in the following.
Method 1: how to retrieve deleted contacts on iPhone from iTunes backup file
If you've synced before you deleted your contacts, the missing contacts s are still in your most recent backup. However, if you sync after deleting those contacts, the chances of recovering them drops. Do not sync your iPhone once you discover your contacts are missing.
Recovering deleted contacts from a backup via iTunes requires you to connect through your computer. While in iTunes, open the "Summary" tab for your iPhone. Select "Restore Backup" and iTunes will reinstall the most recent backup on your iPhone. This restores any data that was deleted after this backup was made, such as contacts, text messages, photos and apps.
Method 2: how to recover lost contacts on iPhone with iCloud Backup
Your iPhone automatically creates a backup of your data to the iCloud daily when you are within Wi-Fi range, lock your screen and connect to a power source. To restore from an iCloud backup, you'll need to wipe your iPhone first to erase all the current data; tap "Settings | General | Reset | Erase All Content and Settings." Once your data is erased, you're prompted to set your phone up as new or restore from a backup. Select "Restore from iCloud Backup" and enter your Apple ID password.
Method 3: Retrieve Lost iPhone Contacts with iPhone Data Recovery Program
If it's been a while since iPhone contacts missing, or you've backed up since deleting your text messages, all is not lost. Third-party data recovery software can scan your iPhone for deleted data information and enable you to restore it.