What do I do if the scorebook and the scoreboard disagree?

The official scorebook governs. In any controversy, the record in the official scorebook is accepted unless you (the referee) have knowledge that lets you rule otherwise.

How it should play out:

1. The scorers verify the scoreboard throughout the game and keep the running score, so a mismatch should be caught quickly.
2. When there's a score dispute, the scorer signals at the first dead ball and you come to the table.
3. Compare the official book with the running score. If there are other (non-official) scorers, they must compare their records with the official scorer (Rule 2-11-11).
4. Correct the scoreboard to match the official book, unless you have direct knowledge of the play that shows the book is wrong.

No timeout is charged when a scoring, timing or alternating-possession mistake is prevented or fixed. The official scorebook must stay at the table, available to you, until you approve the final score.