Answer
Dunning is the systematic sending of payment reminders to customers with overdue balances, escalating in tone and urgency over time (friendly reminder, firm notice, final demand). Automated dunning schedules reminders based on aging so collectors focus on higher-value or disputed accounts.
Real-world example Automated dunning emails go out at 7, 21, and 40 days overdue, freeing collectors to phone the largest balances.