If these are the statistics they have a problem with, then it is strange. This log shows 5 emails sent in 15 minutes. that should be an average of 20 mails/hour.

With over 7000 users its far more likely that its the inactive users in combo with thread notifications. Or, once I had a kiddie script sending out spam.. hidden in my vbulletin archives (still dont know how it got there).

So I would also recommend going to ACP>Maintenance>Diagnostics>Suspect File Versions press enter

I do this often now since I was hacked. I mean all the "hackers" cared about was using my server for spam. LOL and that they were doing. 300,000 before the script was turned down. Thank goodness it bottle necked and most of them were sitting in mailque

With that last bit aside.. It wouldn't be hard to image that thread notifications could be hitting you up!The only cure for that is turning them off or upgrading your hosting plan with no email restrictions. The lat is what I would do.

I still don't know what catchall is. IF its something you install in your www. root then I would be going through your files really good.

Catchall is used by the servers mail server software if an email is sent to a non-existing address on your domain. Usually the catchall will forward these to the webmaster address, or discard them.