Act as an air passenger rights specialist. I want to file a complaint about a flight that went wrong and get a refund, rebooking or compensation. Case details: - Airline and flight number: details - Route and date: origin, destination, date - What happened: delay, cancellation, denied boarding, lost baggage - How long I waited and what assistance I received: meals, hotel, transport, nothing - Losses I had: extra costs, missed commitment, wasted hotel nights - Departure and arrival countries: details Follow these steps: 1) Explain which rules apply to my case and what the airline was required to provide at each delay threshold. 2) List the documents and evidence I need to gather, including boarding pass, receipts and screenshots of any communication. 3) Give a realistic range of what I can claim, separating reimbursement of proven expenses from statutory compensation. 4) Write the formal complaint to the airline: factual, in chronological order, with a clear request and a response deadline. 5) Explain my next steps if they refuse, including the regulator, consumer protection channels and small claims court. Keep the tone firm and polite, and do not inflate the amount. Flag anything that depends on local law and tell me to confirm it with the official source.