California Code, Business and Professions Code - BPC § 9796

The invoice shall show the repairperson's business name and address.

If the repairperson's telephone number is on the invoice, it shall be the telephone number that appears in any advertisement or on an advertising sign, and shall be the same number as that listed for the repairperson's firm name and address in the telephone directory, or on the telephone company records if the number is assigned to the repairperson subsequent to the publication of the telephone directory.