Start with the evidence
Choose the customer and the statement date, then gather the relevant source records. Keep the reporting cut-off explicit so that a later payment is not accidentally included in an earlier snapshot.
Work through the example
Two example invoices total USD1,200 and a linked payment is USD400. The simple remaining amount is USD800 before any other adjustments. Check each line rather than trusting only the final statement total.
Make the next step clear
Resolve unexplained differences and label the statement date clearly before sharing. Retain the version sent and the sources used. A summary should not silently replace the underlying documents or imply a payment was received without evidence.
Keep the source context
An invoice record and a customer conversation provide different evidence. Keep original document references stable while adding dated notes about replies and related payments. These guides concern clear administration, not collection tactics or promises of automated money movement.