All mails disappeared on its own

Hi, I’m managing a server for a client. They told me that all their mails from all their accounts went missing from before 22 August. Only the mails they’ve received are lost, and the mails they sent are OK. I have been only logging to my server via SSH to redo the SSL every two months, other than that I didn’t do anything, as the content on it is static and was finished for over a year.

Another weird thing is, the only mail I was logged in myself was the admin mail, and mails for that account did not seem to disappear, only the other 6-7 mails, including the info one.

By redoing I mean that I go CyberPanel, issue SSL for both domain and mail server, restart postfix and davecot with this command:

postmap -F hash:/etc/postfix/vmail_ssl.map
systemctl restart postfix
systemctl restart dovecot

Unfortunately, I don’t have a backup. What could be the reason this happened? How can I recover my mails? I didn’t do anything other than what I told above, currently I’m in a really bad position. Appreciate any help. Thanks.