I've started reporting repeated spam messages to their registrars.
This was the first response I got yesterday.
While acbdataservices.com domain name is registered with Namecheap it is hosted with another
company. So we cannot check the logs for a domain and confirm if it is involved in sending
unsolicited bulk emails.
However, as we can see the domain name is blacklisted by trusted organizations. Thus we opened
a case regarding the domain name. Please allow about 48 hours for our further investigation.
Then this morning I received this email:
This is to inform you that acbdataservices.com domain was suspended. It is now pointed to non-
resolving nameservers and will be nullrouted once the propagation is over. The domain is locked
for modifications in our system.
So does actually pay off to report the spammers. Obviously it'd be very time-consuming to do it with every email, but when you are getting dozens from the same server then I say give it a shot!