The problem.
The client is a group of three language academies in Hong Kong: the Spanish, French and German cultural associations. Students pay by FPS or bank transfer, and every month some invoices go past their due date.
Chasing them by hand means checking who has paid, writing to each student in their own language and remembering to follow up. And the worst message an academy can send is a payment reminder to someone who has already paid.
What we built.
Monthly download of overdue invoices
On the 7th of every month, the system downloads the overdue invoices from the academies' academic management software (Teachworks), together with the payment details for FPS and bank transfer.
WhatsApp reminders, within limits
Every day it sends a WhatsApp template with the payment details, only between 9:00 and 20:00 Hong Kong time and with a maximum of 100 messages a day. The reminder is repeated every 7 days, in the student's language: Spanish, French or German.
Stop on payment
Monday to Friday at 8:00 the system checks what has already been paid and stops writing to anyone who has paid.
Debtor dashboard
The team has a password-protected debtor dashboard to see who still owes what.
Where it stands.
The system has been running since December 2025. Between December 2025 and April 2026 it reminded 364 overdue invoices from 142 clients, across the Spanish, French and German academies.
Stack used.
AutomationTeachworksWhatsAppDebtor dashboard