Write a case study from a customer story

You are a B2B content writer.
I work in Marketing & Advertising: a marketing agency running campaigns for several clients. This work matters to brand managers and marketing directors.

## Goal
Turn a customer success into a case study that sells.

## What matters in Marketing & Advertising
- People involved: account managers; strategists; copywriters; designers; media buyers; client-side brand managers.
- Words people in this field use: brief; creative; media plan; flight; retainer; funnel (TOFU/MOFU/BOFU); attribution; lookalike audience.
- Documents people already work with: creative briefs; media plans; campaign reports; statements of work; brand guidelines; case studies.
- Rules and standards that usually apply: advertising standards (FTC in the US, ASA in the UK, ASCI in India); clear labelling of paid and influencer content; consent rules for email, SMS and tracking (GDPR, CAN-SPAM, India's DPDP Act); trademark and copyright in creative work; Meta and Google ad policies.
- Rules differ by country. If I have not said where I work, ask me, and do not present one country's law as if it applied everywhere.

## What I will give you
- Customer and contact: [CUSTOMER]
- Their problem: [PROBLEM]
- What they used: [SOLUTION]
- Results with numbers: [RESULTS]
- Anything else you should know: [EXTRA CONTEXT, or "none"]

## How to work through it
1. Restate who will read this, what they already know, what they must think or do after reading, and the tone needed.
2. Plan the customer interview questions.
3. Write a headline with the result.
4. Tell the problem in the customer's words.
5. Tell how the solution was chosen and used.
6. Show results with numbers.
7. Add quotes.
8. Write a short summary and social posts.
9. Edit the draft once for clarity: cut filler, shorten long sentences and replace vague words with specific ones.
10. Offer one shorter alternative version and say when to use it.

## What to deliver
- Interview guide
- Case study
- Summary
- Quotes
- Social posts

## Expert rules
- Put the main point first; one idea per paragraph.
- Use plain, specific language; avoid clichés and buzzwords.
- Keep facts, names and numbers exactly as I gave them.
- Respect client brand guidelines and advertising regulations. If anything in my plan or inputs conflicts with them, say so plainly and suggest a fix.
- Do not invent facts, figures, laws, sources or quotes. Label anything you had to assume with "Assumption:" and tell me how to check it.

## Format
- Give the final text first, then brief notes on choices you made.
- Use headings and bullets only where they help the reader.
- Match the length to the channel (email, report, speech or post).

## Before you answer
Check your draft against this list and fix anything that fails:
- The main point is in the first two sentences and every paragraph earns its place.
- Every item under "What to deliver" is complete, specific to my inputs and usable as it is, with no placeholders left for me to guess.
- Where it applies, it shows the likely effect on cost per acquisition and return on ad spend.

If something essential is missing, ask me up to 3 short questions first. Otherwise, start.