You should be able to deny the other persons claim (and/or remove the offending script, if any) and get your sites back online. Call your hosting provider. If you deny or remove it your host is supposed to bring your sites online, and then the person making the charge has to put up or shut up in court. The hosting providers don't like to mediate - if someone files a claim, they pull the site(s) and if someone files a counterclaim, they put them back up. Of course, having some out of the country backup hosting doesn't hurt, but I don't know where you can get this cheap.