What is the ruling on someone who purchased an item in installments and became unable to pay the installments after having paid half the amount, and is it permissible for the seller to reclaim the item by agreement or by a pre-stipulated condition in the contract?

If the buyer is unable to pay the remaining installments, the seller has the right to annul the contract and reclaim his merchandise, unless the seller knew of the buyer's insolvency at the time of sale, whether the buyer was truly insolvent or a wealthy procrastinator. The contract may include a condition allowing the seller to annul the contract and reclaim the merchandise if the buyer fails to pay. Upon annulment of the contract, the merchandise is returned to the seller, and the paid price is returned to the buyer. The seller is not permitted to take anything from it, because a condition for annulment without compensation is void.