Is it permissible to make use of an item that arrived late after its price had been refunded by the seller, who had agreed to the condition of refunding the amount if the item did not arrive within a specified period?

The questioner is not permitted to take the item and simultaneously reclaim its full price, as this constitutes consuming wealth unlawfully. Allah Almighty says: "O you who have believed, do not consume one another's wealth unjustly but only [in lawful] business by mutual consent." And the Prophet, peace and blessings be upon him, said: "All of a Muslim is inviolable for another Muslim: his blood, his wealth, and his honor." The condition mentioned by the questioner does not imply ownership of the item along with a refund of its price. Rather, it grants him the option to annul the contract and reclaim the price if the product does not arrive within the agreed-upon period.