Blueyonder new password now earlier emails missing

Blueyonder wouldn’t communicate - messages included ‘server says disconnected for inactivity’ [we’d not been inactive] and ‘mailbox not available’. The help line at blueyonder/Virgin Media allocated us a new password. That resulted in us in being able to receive new emails however our existing inbox and sent folders almost entirely disappeared. Emails between Feb 2014 and 13.32 on 7 Sept 2021 vanished from the inbox, and all sent emails before 17.09 on 7 Sept 2021 vanished. Can we retrieve them? We have v 8.2.1473. blueyonder shows Pop3 and SMTP, not IMAP. The ‘enable periodic back up’ was not enabled - I have enabled it today (to monthly and save last 5) - and the last backup showing was 5 Feb 2021. Auto archiving not enabled.

Does this help: How to access your (Blueyonder: Virgin Media Mail) email account using IMAP ?