Does the seller have the right to demand 10% compensation of the item's price after the buyer backed out of purchasing an expensive book encyclopedia in installments, having received the item without providing any personal documents, and this occurring within three hours of completing the purchase?

The sale has been completed between the seller and the buyer. The sold item has been handed over to the buyer, and the buyer is obligated to hand over the price. Regarding the buyer's withdrawal from the sale due to ghabn (exploitative deception/disadvantage), there is a difference of opinion among scholars. If ghabn is proven for the buyer, then the seller has no right to demand compensation. If ghabn is not proven and the buyer wishes to withdraw, it is recommended for the seller to grant him iqalah (cancellation of sale).

Iqalah is a rescission according to the majority of scholars, whereby everything returns to its state before the sale: the buyer reclaims the price and the seller reclaims his goods. Some scholars, however, have held that it is a new sale, in which case the seller is permitted to grant the buyer iqalah for less than the original price.