Apple Mail huge mail corruption and loss

I had 2153 mails on “inbox” and 1052 mails on “sent” on my imap server.

So, normally i use spark mail as mail client, that haven’t got the capability to export or import email messages, neither is saving locally mails, just caching and downloading everytime from the server instead.

So i wanted to switch to Macos Mail but when i have configured my mailserver details, i moved all my messages from imap-inbox to local mac folder (just to test) and from imap-sent to local mac folder too.

The trouble was when moving again back to imap, all the imap-inbox content were moved fine, but on imap-sent there were only 502 instead of 1052 mails.

Basically most of all the emails with the attachment are lost.

My email hosting service is telling me that they haven’t got backup (liars) and timemachine didn’t backup the state on which all the emails were properly saved on my mac.

Is there a way or some suggestion to recover all these loosed messages?