Is it permissible to donate a sum of money on behalf of another person, who is unaware of the story, to avert problems and ill-will, knowing that this sum resulted from a commission-based seller deducting part of the price of goods as compensation for previous support given to a merchant, and then it became clear that the goods belonged to someone else?

The right must be returned to its owner, if alive, or to their heirs. Giving it away as charity is not sufficient, based on the hadith: "The hand is responsible for what it takes until it returns it." There is no need to inform the rightful owner of the reason for their entitlement. As for the work of the "commission agent," it is an agency, and it is not permissible for him to support merchants with his own money and then deduct it from other shipments, because an agent is bound by the limits of his agency and may only act according to what the principal explicitly or implicitly authorizes.