In case you accidentally delete contacts from the Contacts list or your mobile device which has been synced, you can restore deleted info. Deleted info can be restored even as far as 30 days.
Restoring deleted contacts
1. Open contacts: https://www.google.com/contacts/
2. Select More --> Restore contacts
3. Now choose from which time you want to restore contacts
4. Select Restore
Your Contacts have now been restored. Please note that you will receive a notification of the function on the top area of the browser. You can cancel the restoration by clicking Undo.