Rebuild the missing context
Assume the recipient will not remember every date, promise, or earlier conversation. For a message about how to complain about a serious hotel problem, use this factual base: include the product or service, order number, dates, price, fault, prior contact, and supporting record.
Say what needs to happen next
State the decision, information, or practical action you need and include a real deadline only when one exists. Request a specific lawful remedy and give a reasonable response date before formal escalation. Make the immediate next step clear enough that the recipient can answer without reconstructing the entire history.
Avoid making urgency into pressure
Do not exaggerate, threaten staff, publish private details, or demand compensation unrelated to the loss. Use payment, regulator, insurance, police, data protection, or legal channels for fraud, danger, or unresolved rights. Do not make the other person responsible for reducing the discomfort that prompted you to write.