Emails sent from ISP this server rented from (supposedly bare metal) are not shown in maillog. How can this be?

I had a break in on both servers from this company that resulted in a
mountain of outgoing spam. I powered off the other one in LA. I did a
fresh install on this one and I have tail -f /var/log/maillog running in
tmux watching it carefully and constantly since then.

Now these emails are the only ones arriving and not seen in the maillog.

I am very concerned about this.
What should I make of this?

Discussing the break in is a topic well worth discussing at a later
date, but I need to know what to make of what is happening right now.

Any help is appreciated and if I need to I will move elsewhere.

--
Regards,
Chris Bennett