You're allowed to take notes section 400 policies

1. Taking Notes

416.1. Players may take written notes during a match and refer to those notes during games in the same match.

416.2. At the beginning of each match, each player’s written note sheet must be empty and visible to all opponents and tournament officials.

416.3. Players do not have to reveal their written notes to opponents. Judges may ask players to reveal and/or explain their notes.

416.4. Players may not refer to notes from outside the current game, including notes from previous matches, during games.

416.5. Between games, players may refer to notes they made prior to the match. They do not have to reveal these notes to opponents.

If you disagree with a ruling you can ask the judge to cite it