Members from a forum you host are harassing and hacking me/my forum

Hi, I'm sorry to bother you, but something horrible happened to me courtesy of one of the boards run on your service. http://forum.rpgsonline.net This is their address. http://forum.rpgsonline.net/index.php?topic=77.0 This is the topic thread in which they discuss my site, and me, and one of their members said that he was going to gladly hack my site. Then he did, and I ended up having to go to my service provider to have the board restored. I am still cleaning up the > mess. Now they are talking about me badly and posting my forum on bad sites. This place is dangerous and I will get the law in involved if there is any way I can. First I need to know what my recourses are. They won't get off my Cbox now and leave me alone. Sincerely, Wynn