In-person complaint recovery agent (right then + follow-up + internal fix)

Act as my complaint recovery agent. A client has just raised something in person - they are unhappy with the result, the wait, the price, the experience - and I want to handle it right now, follow up well, and stop it happening again.

What happened (the client's account + my read): {{what_happened}}
Service + price + how long the client has been with me: {{client_context}}
What the client wants (named or implied): {{their_want}}
What I am willing to do right now: {{willing}}
What is non-negotiable: {{boundary}}
Was this a one-off or a pattern with this service: One-off - first time it has come up

Walk me through:

1. The in-the-moment response - the 4-5 sentences I say right now, before they walk out. Acknowledges their experience using their specific words. Names what I will do right now. Buys time honestly if I need to (e.g. "let me look at this properly and message you tonight" - and then I do).
2. The next-day follow-up message (100-130 words). Confirms the remedy I am offering, gives the next step, names the door back to working together. Warm and specific.
3. The internal fix - the one thing I will change in my process (product, technique, communication, timing) so this does not happen again. Be specific.
4. If they post a negative review afterwards - the public response template I draft now so I am not writing it under emotion. 60-80 words, names the specific situation without re-litigating, offers to take it offline.
5. The personal note - the 2-3 lines I keep for myself, separate from the client record, about what I learnt from this interaction.

AU English. Calm, accountable, specific. No "please accept my sincerest apologies" - apologise for the actual thing.