It sounds like you may have had a good whistleblower case. If you complain about an illegal act that your employer is committing to a government agency or a person at your company that has the power to have your complaint investigated, or if you refuse to perform an illegal act, you are protected from retaliation. However, you must usually file your claim within two years or you will lose your right to file a lawsuit. Did you file with a government agency or hire an attorney? If so, your right to sue may have been protected or extended. Otherwise, you may be out of luck.