What are my options if my broker decides not to pursue with the Real Estate Contracts?

About a year ago I wrote a one year listing on a residential property. The next day my client called and asked that it be withheld from MLS until his attorney could get the home excluded from their recent bankruptcy filing. I had them sign written instructions to withhold the property from MLS. I put the property in MLS as “withhold”. During the listing period another broker listed and pended the property. It is currently in escrow and should close in the next couple of weeks. The other broker knew that there was an active (but withheld) listing on that property because our MLS notifies whoever is doing the entry in the system that there is another listing open. Because of a personal friendship between my broker and the offending broker I don’t think that my broker is going to side with me on this. My loss on this decision would be in excess of $6k. IF my broker decides to not pursue this what are my options? (Keeping in mind that listings in California belong to the broker, not the associate.)