Originally posted here by abbasali
Spams can be a pain in the backside. To circumvent this issue, I use the following two programs 'eMailTracking Pro' and 'VisualRoute'. These are neat little toys to drill down to the originating IPs. You already have the logs. So, give it a shot and you might have more specific data for the proper authorities.
Hope this helps!
Abbas

VisualRoute 6.0 will do the trick for tracing. Go to www.download.com and get the trial version to check it out. After you establish their identities, contact the authorities. If, upon further investigation, it turns out that THEY have been hacked in a manner that makes them appear to be the source of your woes, you've picked up a mighty fine marketing tool to sway their customers in your direction. After all, who wants an insecure, or unethical for that matter, ISP? Best of luck to you!