There are several options that allow you to restore your contacts, and undo any recent changes.
Restore your Google Contacts:
Your contacts are automatically backed up by Google. So if you ever need to restore your contacts to an earlier state, it's very easy to do as long as you've synced your contacts with Google as least once. Follow these steps to restore your contacts:
- Go to https://contacts.google.com
- Select More > Undo Changes. This will restore the contacts in your Google account.
- To restore the same contacts on your iPhone, sync again
Restore your iCloud Contacts:
If your contacts were also synced to iCloud.com, you can easily restore these contacts as well.
- From your computer, log into iCloud.com
- Go to Settings > Restore Contacts
- Then restore your contacts to a date & time when your contacts had not been deleted. Then sync again with this app. Now your contacts should be restored both on Google and iPhone.
Restore from your device backup:
You can also restore one of your backups made by the Contacts Sync app. To do so, go to Contacts Sync > Contacts > Backup Contacts, select the desired backup, and proceed to restore it.