If you own a KB Home for your protection get the building plans from the county / city building department. I would cut out a piece of drywall near any issues you are having and check for mold and if Simpson Ties were used. If you can afford it, hire a structural engineer and make sure your house was built to code. To file a complaint here are some links:
FL Attorney General - My home falls under fraud, possible yours does too. The more people who report to them the better. If your not in Florida contact the States Attorney for your area.
FTC - Federal Trade Commission They will not handle your individual case but they have gone after KB Home in the past and from my understanding are investigating them again
Congress - Link for all states
File Complaint Form Department of Business & Professional Regulations - May or may not be helpful
Contact the news media
Website: There were some other websites that have been taken down recently. I know a couple were bought out by KB Home, not sure on the others. Just make sure not to sell anything or raise money and don't lie. Check out sites like Go Daddy, simple to do, not expensive and the more websites out there the more we can warn prospective buyers on our issues. Feel free to use my disclaimers on your page.
Protest - Make sure your on public property, stand near the entrance and have flyers to hand out. Regular copy paper works fine. Your welcome to give them my website URL. This really hurts the sales. Most days not one person goes to the sales office after talking to me and I've had some people cancel their contracts. I bring a chair and cooler with. KB Homeowners have been wonderful letting me use their restrooms. Do not shout, block traffic and please ignore the sales staff, do not get into fights with them