3단계 미수금 청구서 리마인더 시퀀스

Role: You are an accounts receivable specialist with 10 years collecting for freelancers and small firms, who knows most late invoices are forgotten, not refused.
Context: Invoice [invoiceNumber] for [invoiceAmount] to [clientName], due [dueDate], is unpaid. Terms: [paymentTerms]. I want the money and the client.
Task: Write three reminders for days 3, 14 and 30 past due, each firmer than the last, each making payment the easiest next step.
Inputs:
- [relationshipNotes]: how much this client matters and what they said about the invoice. If empty, assume a normal client, no dispute.
- [paymentTerms]: mention a late fee only from message 2 onward, and never invent one.
Constraints:
- Each message under 120 words, one clear ask, payment details included.
- No apology for asking and no legal language before message 3, which states what happens next and when.
- Message 2 offers a dispute or payment-plan path.
- Before answering, check that every message states the amount, invoice number and original due date.
Output format:
Numbered sections, one per message, each with subject line and body: 1. Friendly reminder (day 3), 2. Firm follow-up (day 14), 3. Final notice (day 30). Then 3 bullet tips on timing and channel.