Freelancer.com a bad site for workers

Has anyone else here found freelancer a bad site for workers? I think, from the point of view of workers, that the site is little more than a scam or a fraud. Recently worked there on a project, and the employer refused to pay! I arbitrated, and freelancer ensured that he paid me, then let him put a 'revenge comment' in my feedback! What sort of crazy system is that? How can I ever arbitrate against a non-paying employer in future. And if I can't, what protection do I have on this worthless scam or fraud site?