Megan's Law

[Farallone]

Here's my situation. I've been a regular member of an online chatroom for 19 years. I have developed friendships and relationships through it. Lately two members have come in and are posting that I'm on Megan's List. Which absolutely is not true, never have been. The member that originated the post admits he's spreading the rumor. Both members continue to post that I'm on the list. They now refer to me as "Chester the Molester". Neither one of the users know my real name or even what city I live in. What they are posting is a straight out lie. I do however know what their real names and addresses are. I have tried contacting and reporting them to the internet service that maintains the chatroom with no results. I'm hoping somebody can guide me on how to proceed with making this stop. I live in California.