What is the ruling on a pharmaceutical sales representative selling medicines to a distributor to reduce the overall price, knowing that the distributor will sell them in other representatives' areas, to avoid company penalties?

Punishing an employee for not achieving a certain sales target is impermissible (غير جائز), an injustice, and an unlawful appropriation of people's money. What is permissible is to punish them for negligence in the core duties of their work. Those in charge of the company should fear Allah regarding the employees, and the questioner should advise them.

As for the representatives (مندوبين), they are agents (وكلاء) and are not permitted to act except within the limits authorized by their principal (موكلهم). What they have done is not valid unless approved by the principal.