Is purchasing land from an association considered valid if its ownership was not confirmed at the time of agreement, and what is required to rectify the purchase?

If the association sells the land after it has taken possession of it, the sale is valid, and there is no need to renew the contract. However, if it sells it by installments before taking possession, the contract is invalid, and it must be renewed after the association has acquired and taken possession of the land. This is based on the Prophet, peace and blessings be upon him, who said: "It is not permissible to combine a loan and a sale, nor two conditions in one sale, nor profit from what has not been guaranteed, nor to sell what you do not possess."