Apologies again for the interruption in service. Emails sent to a server that cannot receive them are not usually "lost." The basic is answer is "no" you did not lose email. Though delivery may have been delayed. If you want to get a basic understanding of the delivery cycle between the mail servers, read on:
The typical cycle that occurs when mail delivery is having issues goes like this:
1) The sending server attempts to make a connection to the sending server and cannot. It sets the email aside for delivery to the destination server to try again at a later time.
2)Sending server attempts to connect and send again, but again puts the email aside.
3)This cycle occurs for however many times they have their email server set to retry. If the retry cycle to deliver email is exceeded, then a bounce message is sent FROM the sender's own server to the original sender of the email. If the destination mail server can reply, then the bounce back message would come from the destination server with an error message.
If the message made it to the destination server (the sending server successfully connected and was able to hand off the mail to the destination server successfully), BUT the mail server is heavily loaded due to high resource consumption. This means that the server is having difficulty processing all incoming requests (for mail or otherwise). The mail will still processed as per what has been received, but much slower because the mail server still requires the server processing resources to finish delivering the mail. If there is a problem with an email received then it would send a bounce back to the sending mail server.
So, in essence, mail is not lost - it's either successfully delivered or not - and the servers note that and send messages BACK to the server or a bounce is sent from the sending server when a connection to the destination mail server cannot be made.
I hope that makes sense. The bottom line is that you should not have lost any email. Any email that was sent and not delivered would send a bounce back to the sender. They would then have the option of sending again or sending a different message. It's difficult to judge if a mail has failed delivery because the retry time to send email is NOT standard - it may differ from mail server to mail server.
Let us know if you have any further questions or comments.
Many messages did appear within a couple of hours after restoration, confirming your response.