The story of Job is wisdom literature, not historical literature. There are no claims of historicity; the stuff never happened to a guy named Job. The book poses a philosophical scenario to address a theological question: What kind of person is God? The book explores God's policies about suffering in the world, whether righteousness earns a person blessings, and whether or not evil people ever get what's coming to them. The Adversary proposes that it's counterproductive for God to reward goodness, because it makes us all less-than-good (we are good just for the prize). But then we find out that it's counterproductive for good people to suffer, too. It seems that God is caught in the middle: he gets criticized for blessing, and he gets criticized for allowing suffering. This is what the book is going to sort out.
So saying, it's not historical; it never happened. How do I know that?
1. Inverse similitude: Preciseness of details strike as unrealistic (exactly twice as many kids?)
2. Dialogue: Repetition (exact) is unrealistic to real life.
3. The characters speak in poetry. Really?
4. Dialogue in heaven could not have been eye-witnessed. Scenes in heaven are rare in biblical literature.
5. Symmetrical arrangement of speeches. In history, things don’t happen so cleanly.
6. Complete idealization of hero (Job). Not realistic.
7. No historical setting is given.
That's why God didn't give Job the same kids back. It's a treatise, not a historical record.