What is the legal ruling regarding selling a car, and the buyer claiming the existence of defects in it after taking possession, and demanding a full refund along with shipping costs, knowing that the seller had informed the buyer of the apparent defects before the sale?

Resolving disputes is done through the judiciary, as it is best equipped to hear both parties and issue an accurate judgment, whereas a Mufti hears only from one party. As for the defect that grants the buyer the option (of returning the goods), it is that which usually diminishes the value of the sold item or frustrates a legitimate purpose for its purchase. The jurists have agreed upon this meaning, with slight variations in wording. If the sold item is returned due to a defect, the cost of return is borne by the buyer, unless the seller was aware of the defect and concealed it, in which case the cost is then borne by the seller.