Dirk here! I firmly believe the CSLB got me my resolution (which was a complete replacement of my pool's surface), but not in the way I was expecting. The CSLB doesn't actually have that much obvious leverage over a contractor. The extensive complaint I filed with them is not even public (which was a major shock to me). And I had all but given up on them, then after a few weeks my contractor ponied up the full amount. I never did entirely understand how it happened, but my CSLB case worker explained that she was talking to my contractor, negotiating in effect, and she alluded to exerting pressure on him in some way. However she did it, it worked.
If your contractor is bonded (legally he has to be), that is another resource. But it is separate from the CSLB. You have to pursue each separately, the CSLB doesn't go after the bond on your behalf. I didn't get that far, and frankly I wasn't too optimistic about that path, since the Bond company is, in essence, an insurance company that also determines itself if it is going to pay out!! Something like that. Talk about conflict of interest. My case was settled before I had to go that route.
Go on the CSLB website and find the complaint form. Fill it out and start the process. Someone will call you to get your side of the story (and review your supporting doc's), and that same case worker will call the contractor to do the same. They will then attempt to negotiate a resolution. CA is pro-consumer, so if your story is legit, they'll fight a little harder for you than the contractor. You might also consider filing the complaint with the contractor's bond company at the same time, to start that process. (All this stuff takes time.)
My contractor wasn't too bright, so he may have been intimidated by the CSLB complaint. Or it's possible he had multiple lawsuits going (yah, he was that bad, and there was some indicators that he was in trouble with more than one customer), and so needed to get me off the radar in order to better defend his other problems. Who knows.
Whatever you do, don't give the contractor another dime. You don't have to at this time. CA law recognizes something called a Good Faith Dispute, which you are now in, and that suspends your obligation to pay anything until a resolution is reached. Now, if it's determined that the contractor is somehow not to blame, he could claim interest on the unpaid funds for some period of time, but that is not likely to happen in your case.
Also, I chose to cease all verbal communication with my contractor, and communicated exclusively with certified letters. Others here did not support that approach, claiming I should have taken a more "friendly" approach. I don't agree. I knew after the first conversation with him that this was going south, and I wanted everything in writing. As I mentioned, he wasn't too bright, and in his return certified letters to me, he basically hung himself with statements that would have been great ammo in court, all in writing, all certified mail!! If I had only used phone conversations, or face-to-face meeting, then I would have been in a much weaker position (he-said-she-said scenario). Document everything. Do everything in writing.
Good luck, keep us posted...