Useful material includes the complete challenged communication, details of the sender and recipients, its date and distribution channel, and a chronology of later responses. For online content, preserve the URL and time. For oral statements, identify possible witnesses and retain an unprompted note of the discussion.
Also identify material that can test the truth of the assertion. This may include contracts, performance records, quality documentation, correspondence or accounting records. Confidential information should not be forwarded without control. For an initial assessment, it is enough to describe factually which evidence is available.
Commercial consequences should be documented specifically but cautiously. Record customer questions, cancellations, price changes or other responses with their date and source. Timing may be an indicator, but it does not replace analysis of causation and legal attribution.