Reckon Accounts Premier Customer Discrepancy

Reckon Accounts Premier Retail Edition (not hosted), One of my customers is showing an outstanding balance in the Customer & Jobs List, however when I go to bring up the customer's outstanding invoices using Open Balance report, there is nothing outstanding.  Customer account should be zero, as it is correct that there is nothing owing.  Accounts Receivable report also does not show anything owing.  Why oh why do I have this anomaly, and how do I fix it?