A man sold his goods to another, to be paid in monthly installments totaling nine thousand riyals, and they agreed that if he delayed paying the amount, he would pay

The Shaykh : He says: A man sold goods to another, to be paid in monthly installments, and the price of the goods is nine thousand riyals. They agreed that if the buyer fails to make the payments, he will pay an additional amount of one thousand riyals, and this additional amount is to be given to the person who collects the money from him. What is the ruling on this sale?
This condition is defective and invalid because it is riba (usury or interest). When a person sells a commodity for a price, he cannot increase that price. Therefore, the condition is invalid and not valid, and he is entitled only to the price for which he originally sold it.