You may be able bring a legal action against any and every person who has made defamatory statements about you online. A defamatory statement is an untrue factual assertion (such as that you distributed child pornography) which tends to damage your reputation (which this assertion would). In a legal action, you can seek both a court order ("injunction") requiring them to remove such statements and not make them again, and also monetary compensation ("damages") for the harm to your reputation. From what you write, it would be worthwhile for you to consult with a personal injury attorney about your situation. Good luck.