Dealer only has 5 days to let DMV know of the sale and 30 days to get you registration. Failure to do so is a violation of law and enough to unwind the deal and get you all of your money back, almost like you drove it for free all this time. No reason to call them anymore. They should also have to pay your atty fees. There are less than 100 attorneys in CA who know this area of law and handle it, so, most practice statewide. Offices (like mine) who do this will generally give you a free document review and if they take it, do so on a no fee basis.
I support Mr. Kaufman's response in all respects. He is known and respected expert throughout the State on these matters.
You may also want to consider making a complaint against the Sales license of the Dealer. DMV's sales licenses are subject to revocation on the kind of facts you have described, although their resources and enforcement policies are inconsistent, and there is no accounting for the timeline of any enforcement action. Still, there is nothing to be lost by putting the dealer at risk for State license revocation action. You can proceed civilly as Mr Kaufman advises at the same time.