Build the history from actual transactions
For each relevant payment or deposit, preserve the date, source confirmation, tax subject, intended period, and available reference. Keep scheduled, completed, failed, and reversed transactions distinguishable. A bank withdrawal and a tax-account record may raise different questions, so neither should silently replace the other. Put the related return and notice alongside the transaction evidence while maintaining their separate roles.
Investigate the mismatch before labelling the result
When a figure or period seems unfamiliar, record the exact difference and the supporting sources. Consult the appropriate current official payment or deposit information and use the relevant account process to seek clarification. Do not assume a working reconciliation establishes that every obligation has been met. If assistance is offered, define the review period and follow-up responsibility. Save an actual explanation or correction separately from an expectation so later discussion can distinguish what was proposed from what the account evidence confirms.