In a court case, there are two sides (called ‘parties’). Normally each side has a lawyer. The judge, or magistrate, sits up the front of the room behind a very high desk. Everybody must speak to the judge or magistrate, and not each other.
The lawyer for the person making the complaint explains the problem, and the lawyer for the other side explains their side of the story. You, and the organisation or person you are complaining about, do not get to say very much. When you do get to say things, you can only talk about the specific problem that you are complaining about. At the end of the court case someone wins, and someone loses. The judge or magistrate decides what happens next.