Write a formal letter: complaint, request or notice

Write a formal {{letter_type}} letter from me to the recipient below. Someone else may read it later, such as a manager, a regulator or a mediator, so it should be calm, factual and specific: a reader who knows nothing about the matter should understand what happened and what I am asking for.

From: {{sender_details}}
To: {{recipient}}

What happened, with dates, amounts, reference numbers and earlier contacts:
"""
{{facts}}
"""

Contract terms, policy or warranty wording that applies, pasted as written, or "none":
"""
{{relevant_terms}}
"""

What I want: {{desired_outcome}}
Date I want a response by: {{response_deadline}}
What I will do if there is no response, or "nothing stated": {{next_step}}
Documents I am enclosing, or "none": {{enclosures}}

Task: Write the letter in this format, on one page of 200 to 350 words:
1. My address block, the date, and the recipient's name, title and address.
2. A subject line starting "Re:" with any account, order or reference number.
3. Opening paragraph: the purpose of the letter in one or two sentences.
4. The facts in date order, with amounts and reference numbers.
5. The specific outcome I want and the date I want a response by.
6. My next step, only if I stated one.
7. "Enclosures:" with the list, then "Sincerely," and my name.

Rules:
- Keep the tone firm and polite, with no sarcasm, emotion, exaggeration or blame beyond the facts, because a calm letter is more credible to anyone who reads it later.
- Quote terms only from the wording I pasted. Do not cite laws, regulations or rights. If a legal right might apply, add one line after the letter suggesting I check with an advice service or a lawyer before sending. The letter is not legal advice.
- Do not add threats or deadlines I did not give.

If anything is missing, such as a date, amount or reference number, do not guess: write it in square brackets, for example [date of purchase], and list every bracketed item after the letter under "Fill in before sending".