Report the names using a harassment ticket to a GM. It's the only way. I've done it. If you cannot remember the names while filing the report, take a screenshot. Better yet, at the end of the day, make a list somewhere of all the names and then send the report into a GM. I've done that. Screenshots of the chat log and character names help with remembering and getting evidence.

EDIT:
Btw, the GMs WILL do something about the spammers and RMT. It just takes time as they have to get other reports as well, so don't think they are ignoring you. I've reported RMT, and a few days later I don't see them anymore. Could be just my server.