Is it permissible to take the commission difference from a client by raising the price on him without his knowledge, due to the company not giving the due commission and the manager reducing it to benefit from it at the end of the year?

Firstly: The employee's commission must be agreed upon as it is part of the salary, and to avoid disputes. The company is not obligated to give a customary commission, but rather one based on the agreement.

Secondly: It is not permissible for an agent to increase the price of an item for his own benefit without the principal's permission. Otherwise, it is a betrayal and an unlawful appropriation of money. The profit from the sale belongs to the principal, and the agent is only entitled to his agreed-upon fee.

Thirdly: If the company explicitly agreed upon a specific commission and then refused to pay it, and the employee gains access to some of its money, he is permitted to take his confirmed right, provided that he does not increase the price of the item, and does not expose himself to accusation or punishment.