You have the usual routes, e.g, the BBB, state Attorney General Office of Consumer Protection (if your state has one), small claims court and for the alleged offending A&P, the FAA through a complaint with the FSDO or some other place. Or you could use Fecesbook, Twitter, Instagram and whatever other social media you like and have a field day blasting them by name. You could also hire a lawyer and try to pursue the Broker and the Seller for fraud, and many of its close cousins. But in most instances, you will need some evidence to back your claims; a mere allegation is not enough. That’s why social media is probably your best resource - alternate “facts” and alternative reality is very much welcomed and indeed encouraged. You can create all the facts you need with no proof of any kind required. Hey, people get elected to public offices and appointed to high government positions using this technique.