The best thing you can do whenever you receive these kinds messages is to report the senders via the right-click > Report Spam or Report Harassment option. Don't click on any links that the message may refer you to, though, as they may contain malware like Trojans and keyloggers. You'll want to avoid sharing the links publicly, since that could put other players' accounts at risk, too.

In fairness, many of us reported him on his first attempt to spam us - weeks or months ago.