You could complain to the Board of Licensing. But, that may not be fast enough. Your only other recourse would be to sue for breach of contract against the broker and ask for a temporary restraining order to require that the closing attorney not distribute the commission to the broker until the court rules on the breach of contract, or until the broker agrees to pay you the money that you are entitled to.
You would also be entitled to attorney's fees if you prevail, but if the broker is insolvent, then it won't matter much.
You could tell the broker now, that unless he/she provides a letter to closing now stating that you should be paid $X directly from closing, that you will be forced to file suit and prevent the release of the money and for recovery of the other commissions owed you.
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