Is it permissible to reclaim a residential plot of land that was legally transferred and sold to another person who is unwilling to return it?

If the sale is a waiver of the right to purchase, then retraction is not permissible, and the land must be handed over. However, if the land sold is unknown or not owned by the seller, the sale is void. In a sale, the price and the item sold must be known, and one must not sell what one does not own.