What is the ruling on selling a product displayed in an online store, then purchasing it from the manufacturer and shipping it directly to the buyer after the customer places an order?

The apparent meaning of the question is that the inquirer is an agent for the product owner, selling their product and setting a price for it, with permission to increase it. There is no objection to this. However, the inquirer's statement, "I buy them from the factory and ship them directly from the factory to the customer," creates an issue and contradicts the agency on behalf of the product owner. If the transaction is conducted according to an agency contract, then there is no objection to it. The inquirer displays the merchandise that its producer has authorized him to display, and has set a price for it. He sells it at this price, and any excess amount is his. He informs the producer of this so that the merchandise can be sent to the buyer, and the inquirer sends the agreed-upon price to the producer, keeping the excess amount for himself.