Mac Mail deleted an entired thread of emails without my consent

This never happened to me before but yesterday I had a big thread of emails open on my Mail app (~60 emails) and I don't know how but today they're gone. This happened at my office.

All the emails my client and I exchanged for the past 3 months simply disappeared without my consent.

I've tried searching for them directly on the server through Round Cube and they aren't there (not even on the Trash, Junk or Archive folders.) I've just arrived home to see if my sleeping MacBook hadn't synced in the meantime, but it turns out it does even in sleep mode.

I don't have Time Machine enabled and don't do backups of my Mac because I have everything on iCloud.

Does anyone know if there is some kind of internal trash / cache or any other place I can search for this emails?

Thank you

Don't know what your current settings are, But for future safety, in mail → preferences → accounts → mailbox behaviours, keep trash mails for a month. In case they were deleted by an inadvertent action.

If there were a backup, ~/Library/Mail/Vx (where x is a number) would have the mails. You can try though.

You can also ask your IT department(if any) to check in their backups. Most of them keep it for some days.