Cal. Insurance Code § 679.9

If an insurer changes the annual premium under a policy specified in Section 675, it shall, within 15 business days of a request by the insured, inform the insured in writing of each of the following: (a) The amount of the premium increase or decrease in comparison to the premium charged in the previous year. (b) The reason or reasons for the change, including, but not limited to, the deletion of a loss-free credit, the application of a claim-related surcharge, or any other reason related to a claim or policyholder inquiry. (c) A brief statement indicating each of the following: (1) That the consumer may contact their agent or the insurer with any additional questions regarding the premium and providing the telephone number for the insurer’s representatives who are capable of responding, and authorized to respond, to consumer inquiries and complaints. (2) That if the insured has contacted the insurer to discuss a premium increase and the insured remains unsatisfied, he or she may contact the department with any inquiries or complaints. The statement shall include the telephone number of the unit within the department that responds to consumer inquiries and complaints.