You need to report him to the ethics and discipline committee immediately. The website is cabar.ca.gov. From a brief reading, I can tell that the lawyer violated several ethics rules. First, he cannot bring in another lawyer to represent you without your consent. To do that, he may also share fees with the trial lawyer, which is another violation. I suspect that was the reason he demanded $12000. For the six months before trial, did you hear anything from the lawyer? Did you try to contact him? Sounds like he pretty much abandoned you since you had no choice but go to the court by yourself. This is a serious matter. Unless there is a court order or you consented to his withdrawal, he violated another ethics rule. If he did not formally withdraw, he is incompetent.
Last one, the fact that he attempted to get the $5200 will subject him to di*****arment, provided you have proof.
For the trial lawyer, unless he had correct reason to withdraw, he violated rules as well and you need to report him too. You just cannot leave your client hang.
Meanwhile, you need to contact a lawyer to find out whether you can file a civil lawsuit to ask the original lawyer to pay for your damage.