What is the name of the California state agency to contact to file a complaint against a car dealership?

My parents bought a 'Certified Pre-Owned' Saab from Martin Automotive Group in Los Angeles and two days later, the engine didn't run. After the fact, I looked up this company with the BBB and it has a D rating. We thought the dealer would immediately take care of the problem, but they were told the Saab (The 'Cert... show more My parents bought a 'Certified Pre-Owned' Saab from Martin Automotive Group in Los Angeles and two days later, the engine didn't run. After the fact, I looked up this company with the BBB and it has a D rating. We thought the dealer would immediately take care of the problem, but they were told the Saab (The 'Cert Pre-owned Saab') has a number of problems and the engine needs to be rebuilt. They were also denied a refund because even though the car was returned in two days after purchase, the refund was requested after four days. I'm furious that a car was sold in this condition and falsely certified and would like to know which agencies will best take action if I file a complaint. Thank You!
Update: Even though the company's actions may not be illegal, I certainly feel they've acted unethically.
Update 2: They haven't responded to BBB complaints in the past. I'm thinking more along the lines of a state agency
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