Asta bought from Xono Co. a truck, payable in monthly installments. As security for the payment of the balance of the purchase price, he constituted a chattel mortgage on the truck in favor of the company. Because of his failure to pay three consecutive monthly installments, the company filed a complaint against him to recover the unpaid balance. A writ of attachment was subsequently issued against his properties. Thereafter, the truck was sold at public auction in which the company was the only bidder for P1,000.00. Since there was still a deficiency of more than P1, 000,00 the court condemned Asta to pay to the company the deficiency plus interest. Is this in accordance with law? Explain your answer with legal basis. (A.L.A.C method)