There is a bit of unclarity in relevant details in the question. There are two kinds of legal outcomes given the apparent scenario. One is that the broker might be criminally prosecuted for forgery, and possibly perjury. The premise here is that he forged a contract and your signature, and also used this as evidence in a legal proceeding. You would need to report the crime to the police, who would investigate and decide whether to recommend this to the prosecution for criminal charges. You have no role in this apart from reporting and testifying.
The other avenue is a lawsuit, to recover the money that you would be owed. Basically, it does not matter that you don't have a written and signed contract. I assume you don't mean that the guy never paid you in those 2 years; let's assume that he failed to pay on your last sale. You sue him for breach of contract. Then, there might be a dispute over what he was required to pay you, e.g. he maintains that it was supposed to be 3% and you maintain it was supposed to be 6%. Then the court will judge who is more believable.
A third option, for regulated industries, is to pursue an administrative complaint (e.g. with BRE), which it sounds like you already did. BRE has no power to compel him to pay you, but they might pull his license. If you didn't get satisfaction from BRE, then you would need to hire an attorney to sue him.