None of this makes any sense. No one sues for $20 and no judge I have ever seen in my decades of practice would tolerate a case of such de minimis value cluttering up a courtroom. Second, California's Business and Professions Code (The State Bar Act) defeats any claim or lawsuit against any person for any complaint or report to the State bar against a member (attorney). No defamation, no business torts, no nada no nothing. You describe a claim by the attorney about a "frivolous" complaint with the State Bar, and a subsequent anti-SLAPP motion. No, here too, your summary falls apart. There is no cause of action for a frivolous complaint to the State Bar and anti-SLAPP laws don't apply in the circumstances you describe.
I don't believe that the Judge "agreed" with any of this, if any of this really happened.
Talk with an attorney if there is any factual basis for this saga. It is plain that whatever the events that have occurred, you have misunderstood and you need legal counsel for clarifying your rights and obligations.
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