Those problems are really sad. We (RSPortugal) had loads of problems dealing with hackers to. I even went to the former RSOF Fansites to ask for help, because a portuguese hacker was rushing on all portuguese runescape players and also RSPortugal.
Whats more impressive on it is that he isn't already banned, with loads of people reporting him for "hacking".
But well, we, fansites, what can we do? A question we ask ourselves many times. Well, we have to battle with all we have against the hacker and prevail, but also to ensure our users that their personal details are safe.