Is dealing with a person who buys goods (cars, lands, houses, recharge cards) at prices higher than their real value with specified deferred payments, then immediately sells them at lower prices – to the extent that his work is confined to signing bonds and official papers without seeing the goods – permissible or impermissible (halal or haram)?

Selling on credit is permissible, even if the deferred price of the commodity is higher than its cash price, provided that the well-known conditions of sale are observed, such as knowledge of the price and the item being sold. Seeing the item being sold is not a condition. It is required that the commodity itself be something permissible to sell on credit. Thus, it is not permissible to sell gold, silver, banknotes, or food for food on credit. It is also not permissible to increase the price if the buyer fails to pay on the agreed-upon due date. There is no harm in a person mediating between the seller and buyer in a credit sale, as long as there is no deception or misleading. As for guaranteeing the buyer or his betrayal, this is up to the seller if he desires a guarantor or collateral, and it does not prevent the sale if the contract is valid and free from ambiguity (gharar) and deception.