tymah you can see the contents of your WebFaction archive by listing the hidden files in the archive directory, eg:
ls -la ~/wf_archive_delivery/mailboxes/name_of_mailbox/Maildir
If you don't see directory names like ".Sent", ".Sent Items", etc then the folders were not included in the archive that you got from WebFaction.
If the folders are present in the archive but you don't see them in your mail client then please email support @ opalstack.com to let us know the mailbox name and the location of your archive so that we can investigate. Thanks!