Is working as a sales representative, which entails convincing customers to buy without mentioning the system's flaws, and where the marketing team lures customers with promises of non-existent gifts, considered "deceiving people"?

The seller, their agent, or the sales representative must disclose any defects that the buyer dislikes or that diminish their desire for the sold item. Otherwise, concealing them constitutes prohibited deception and fraud. If the work of a sales representative involves remaining silent about what is impermissible to keep silent about, then it is not permissible for her to remain with the company. However, if she discloses this to the customer and the customer purchases the service after being informed, then there is no blame upon her, provided her work adheres to Islamic guidelines.