Cal. Health and Safety Code § 1371.39

(a) Providers may report to the department through the toll-free provider line, email address, or another method designated by the department, instances in which the provider believes a plan is engaging in an unfair payment pattern. (b) Plans may report to the department through the toll-free provider line, email address, or another method designated by the department, instances in which the plan believes a provider is engaging in an unfair billing pattern. (c) “Unfair billing pattern” means engaging in a demonstrable and unjust pattern of unbundling of claims, upcoding of claims, or other demonstrable and unjustified billing patterns, as defined by the department. (d) On or before July 1, 2019, and at least annually thereafter, the department shall review complaints filed pursuant to subdivision (a). If the review of complaint data indicates a possible unfair payment pattern, the department may conduct an audit or an enforcement action pursuant to subdivision (s) of Section 1300.71 of Title 28 of the California Code of Regulations.