to restore all items from a contact folder do the following:
get-mailbox | Restore-Mailbox -RSGDatabase “Server\Recovery Storage Group\mailbox Database” -IncludeFolders \Contacts
to restore all items from a contact folder do the following:
get-mailbox | Restore-Mailbox -RSGDatabase “Server\Recovery Storage Group\mailbox Database” -IncludeFolders \Contacts