On rare occasions, an address book will be lost when a user is editing it. This happens when there is interruption in the user’s Internet connection. In order to restore the address book, follow these simple steps:
Step 1: Login at https://mail.psmail.net/mail
Step 2: Expand the address book by clicking the + sign next to Address book on the left sidebar.
Step 3: Click on Edit on the left menu bar. On the top side of the page you will see a Restore Backup option. Click on this to restore the most recent backup version of your address book.