Cleopas Ape died in 1950 and left a parcel of land (Lot 2319) to his 11 children. The children never formally divided the property amongst themselves except through hantal-hantal whereby each just occupied a certain portion and developed each.On the other hand, the spouses Lumayno were interested in the land so they started buying the portion of land that each of the heirs occupied. On 11 Apr 1973, one of the children, Fortunato, entered into a contract of sale with Lumayno. In exchange of his lot, Lumayno agreed to pay P5,000.00. She paid in advance P30.000. Fortunato was given a receipt prepared by Lumayno's son in law (Andres Flores). Flores also acted as witness. Lumayno also executed sales transactions with Fortunato's siblings separately.In 1973, Lumayno compelled Fortunato to make the the delivery to her of the registrable deed of sale over Fortunato's portion of the Lot No. 2319. Fortunato assailed the validity of the contract of sale. He also invoked his right to redeem (as a co-owner) the portions of land sold by his siblings to Lumayno. Fortunato died during the pendency of the case. Was there a valid contract of sale? Explain.