Complaints By Mail
Department of Consumer Affairs
Constractors State License Board - California
https://www.cslb.ca.gov/Consumers/Filing_A_Complaint/Filing_A_Complaint_By_Mail.aspx

To file your complaint by mail, begin by downloading the Construction Complaint form (English | Spanish), or call (800) 321-CSLB (2752) to request that a complaint form be mailed to you.

Gather all printed documentation that you have related to the construction project.
Fill out and sign the form.
Print copies of support documentation requested on the form. It is usually indicated with the words "(Provide copies)".
Mail Complaint form and paper copies (DO NOT SEND ORIGINALS, FLASH DRIVES, OR CDs/DVDs) of support documentation to the appropriate address listed below, based on which county in California the construction project is located:
For work performed in Imperial, Los Angeles, Orange, Riverside, San Diego, or Ventura counties, send complaint forms to:

Norwalk Intake Mediation Center
12501 East Imperial Highway, Suite 620
Norwalk, CA 90650
For work performed in any California county not mentioned above, send complaint forms to:

Sacramento Intake Mediation Center
P.O. Box 269116
Sacramento, CA 95826-9116