Deleted Emails not in Trash

I deleted ALL the emails and I want them back but they are NOT in my Bin/Trash. I have an iMac latest version.

I use Virgin Media as my ISP and don’t use Mail for my emails.

Please help me to get them all back (if it is possible).

My email address is:-

*******@ntlworld.com.

I will be so grateful if anyone can help me.

Thank you,

Very best regards,

Trev.

[Edited by Moderator]