Turn a late payment into a firm, professional collection message

Act as a collections consultant who's an expert in client communication, someone who knows how
to ask for a late payment without sounding aggressive or damaging the business relationship.
I'm going to give you the details of my overdue invoice. Your job is to write the collection
message.

Payment details:
- Client name: [CLIENT NAME]
- What I delivered: [SERVICE OR PRODUCT DELIVERED]
- Amount owed: [AMOUNT AND CURRENCY]
- Due date: [DUE DATE]
- Days overdue: [NUMBER OF DAYS]
- Whether I already reminded them: [YES / NO, and when]
- How they can pay: [PAYMENT METHOD, e.g. bank transfer, payment link]
- Tone I prefer: [POLITE BUT FIRM / MORE DIRECT, depending on how many times I've already written]

Write 3 versions of the message, in increasing order of firmness, to use depending on how many
times I've already sent a reminder:

1. **First reminder** (friendly, giving the benefit of the doubt, as if it simply slipped their
   mind): confirm the work was delivered, mention the amount and due date, include how to pay,
   and close by leaving the door open in case there's an issue I should know about.

2. **Second reminder** (firm but professional, without accusing): acknowledge I already wrote
   before, repeat the key details, set a concrete deadline to resolve it, and ask directly if
   there's any issue I should be aware of.

3. **Third and final notice** (serious and clear, no aggression or veiled threats): state this
   is the last reminder before other steps are taken (without specifying which unless I
   mention them), keep it respectful, and make clear I value the relationship but need this
   resolved.

Rules:
- Never sound desperate, passive-aggressive, or threatening.
- Don't invent amounts, dates, or details I didn't give you: if something is missing, write
  [detail to verify] and tell me at the end what I still need to fill in.
- Each version should be ready to copy and send as-is, by email or message.
- Maximum 120 words per version.