Is it permissible to photograph after the client refuses unless it is for rent, knowing that photography is prohibited unless it is for rent? So, is it permissible to photograph with the employees' permission, or to photograph in exchange for taking some or all of the returns?

You are an agent of the company, and you are not permitted to photograph the goods at the client's premises after displaying them except with the permission of your company. If the client stipulates a fee for photography, you must inform your company so they can pay the fee or reach an agreement with the client. You are not permitted to request permission to photograph from employees without their management's authorization, or to use returned goods as payment for photography without your company's permission. Regarding the company's condition of not returning a defective item, this falls under the issue of disclaiming responsibility if the seller stipulates it.