How do I see customer payments that have not been applied to an invoice?

Use the Payments Received report (Payments Received category). The UNUSED AMOUNT column shows any payment amount that has not been applied to an invoice. Sort by this column to quickly find customers with unapplied credit balances.

The Customer Balance Summary report (Receivables category) also shows AVAILABLE CREDITS per customer for a quick overview.

Learn more about Payments Received Reports and Receivables Reports.