An Aged Debt Analysis is the essential working tool for collectors and the best control document for senior management to monitor trends and weaknesses.
List accounts in order of size - largest debt first.
Computerised Systems - use an open-item version of the statement sent to each account showing all unpaid items - current and overdue - with disputed billings segregated for action.
Manual System - use paper copy statements as above, but change to open-item display as soon as possible (the brought-forward balance method is outdated and generates too many queries).