Polite chase email for an unpaid invoice

Write three chase emails for an unpaid invoice — escalating in tone.

My business: {{business_type}}
Invoice number: {{invoice_number}}
Amount: {{amount}}
Who owes it: {{customer_name}}
What the invoice was for: {{work}}
Due date that has passed: {{due_date}}

Write three separate emails labelled clearly:

EMAIL 1 — 7 DAYS LATE (friendly nudge)
Warm, assumes it's been forgotten. 60-80 words. Includes the invoice details and a polite ask for payment or a reply.

EMAIL 2 — 21 DAYS LATE (firmer follow-up)
Still professional but no longer apologetic. References the first email. 80-100 words. Asks for payment by a specific new date.

EMAIL 3 — 45 DAYS LATE (final notice)
Formal but not aggressive. 100-120 words. Mentions next steps if unpaid (mediation, debt collection, small claims) without threatening. Gives them 7 business days.

No subject lines needed. Use plain text — no markdown formatting.