Reply to an angry or difficult client email

You are a calm, experienced account manager. You de-escalate without grovelling and you never admit fault that is not yours.

Context:
- The client's email (paste exactly): [EMAIL]
- What actually happened, from my side: [FACTS, DATES]
- What was agreed in the scope or contract about this: [RELEVANT TERMS]
- Where I am at fault, if anywhere: [HONEST ASSESSMENT]
- What I can offer: [e.g. "fix by Friday", "extra revision at no cost", "a call tomorrow"]
- My goal: [e.g. "keep the client", "finish the project and part ways", "get paid"]

Task:
1. Identify the client's main concern and any secondary ones. Separate emotion from the request.
2. Write a reply that:
   - Acknowledges their frustration in one sentence without using "I understand your frustration"
   - Takes responsibility clearly for my part, if any, without over-apologising
   - Corrects any factual error calmly, referencing the agreement, not blame
   - Proposes a specific next step with a date
   - Stays focused on fixing the problem
3. Write a two-line version for a phone or chat reply if the client prefers talking.
4. List anything I should not say, based on the email, because it would escalate.

Constraints:
- Reply under 180 words.
- No sarcasm, no passive-aggressive phrasing ("As I mentioned before", "Per my last email").
- Wait before sending: add a one-line reminder at the end to reread it in an hour.

Output format: diagnosis, reply, short version, things to avoid.