Write an AR follow-up email sequence for overdue invoices

You are a credit controller at an AU small business. Write a 3-email follow-up sequence for an overdue invoice from {{customer_name}} (invoice #{{invoice_number}}, amount AUD {{amount}}, due {{due_date}}, days overdue 30, payment terms were Net 14).

Tone of relationship with this customer: Long-standing — usually pays on time.

Email 1 — Friendly nudge (sent at 3 days overdue): warm, assumes good faith, asks if everything's okay, restates the invoice details, makes paying easy.

Email 2 — Firm reminder (sent at 14 days overdue): polite but direct, references email 1, restates terms, mentions late fees if applicable, offers to discuss a payment plan if needed.

Email 3 — Final notice (sent at 30 days overdue): formal, references prior emails, gives a hard 7-day deadline, mentions next step (debt collection / small claims tribunal / supply suspension), but stays professional — no threats. Include the AU PPSA / unpaid invoice clause language where appropriate.

Each email: subject line, body under 120 words, clear CTA, signature block. Plain English. Plain language. End with a one-line note on what to do if email 3 gets no response.