Thanks for contacting us. This is frustrating position -- and you are wise to raise the issue.
If someone is an employee (and not an independent contractor -- as some outside sales are, essentially agents selling on a commission), then California Law (unlike the laws in other states or Federal law) states:
California Labor Code Section 2802
2802. (a) An employer shall indemnify his or her employee for all necessary expenditures or losses incurred by the employee in direct consequence of the discharge of his or her duties, or of his or her obedience to the directions of the employer, even though unlawful, unless the employee, at the time of obeying the directions, believed them to be unlawful. (b) All awards made by a court or by the Division of Labor Standards Enforcement for reimbursement of necessary expenditures under this section shall carry interest at the same rate as judgments in civil actions. Interest shall accrue from the date on which the employee incurred the necessary expenditure or loss. (c) For purposes of this section, the term "necessary expenditures or losses" shall include all reasonable costs, including, but not limited to, attorney's fees incurred by the employee enforcing the rights granted by this section.
You may wish to contact your local California Division of Industrial Relations office to discuss the matter and make a decision if a complaint is warranted and how to proceed. http://www.dir.ca.gov/dlse/DistrictOffices.htm
I wish you speedy resolution of this matter.