Evidently I upset a spammer who now uses my email address in their spam. I keep getting these returned emails from people I have not emailed. the emails are spam emails. Apparently this spammer does not like me complaining to their ISP. When I check the headers most of them were mailed from computers in a botnet that is overseas but because the from line contains my email address they are returned to me. I have already informed my ISP. I know there is not much I can do. >

   There are many viruses out there that take names from a person's computer and puts them in the To and From fields.  Evidently someone who has your email address on their computer is infected with one of these viruses.  When they clean their computer of the virus, the spam emails will stop.
   I doubt that it has to do with you complaining to someone's ISP.  True spammers never let you know what their real ISP is or they have ISPs that allow them to spam (they pay extra money for this).