The official is not your enemy, but not a helper either: they follow a rulebook. Always "Sie", never "du". Politeness opens doors: "Ich verstehe, dass… aber könnten Sie…" works better than pressure. Do not admit fault on the spot: "Ich werde das prüfen" is neutral. Note the name and time — evidence for a complaint. If refused without reason: ask for a written Bescheid — they often reconsider.

• ●"Könnten Sie mir das schriftlich geben?" — the key phrase
• ●Never shout — loud means losing in a German office
• ●Come prepared: max 3 questions, short and factual