Leading Mental Health Billing Services provider in Fremont, California (CA). 12+ years of expert Mental Health Billing Services. Call 888-502-0537 now! Mental Health Medical Billing can be considered a complicated service in technicality and ever-changing regulations, making it challenging to formalize medical billing processes. To bring about some share of uniformity in billing and coding for the hospitals and individual practitioners, the authority for Mental Health in Fremont, California (CA) have come up with new billing processes.