If several years of taxes remain unresolved, ask for help understanding them. A review can identify filing concerns and discuss ways to address amounts owed.
Make a row for a specific period
Use the year or other tax period printed on the document rather than assuming every item concerns your latest return. Give each entry a place for the return copy, filing evidence, the latest letter, and a short unresolved question. If an item cannot yet be matched to a period, put it in an unassigned group and record why. This keeps a missing detail visible without forcing it into the nearest folder just to complete the sheet.
Choose one question to open with
Review the rows for the issue that needs attention first, using any actual instructions and dates on the notice. Describe the uncertainty in a sentence that can be checked against a record. For example, you might need to establish where a payment was applied before discussing the remaining balance. Keep that example separate from your own facts. During a call, explain which years are involved and which documents you can locate; ask what additional evidence would clarify the next step.