Missing Mailboxes ON MY MAC after a system restore

I had a system glitch, Apple wiped my MacBook pro clean and when we did the reinstall from the iCloud, all of my mailboxes as well as the mail in them from "on my mac" is gone, called Apple, they had me to into the Time Machine and although it was backed up, no one knows how to recover them.

Really need step by step info. or is there a service to call remotely that knows how to recover.

I'm really in need of these missing business emails.