Remove duplicate rows

I have a data export from last quarter with customer_id, purchase_date, and amount. Remove duplicate rows so each customer_id and purchase_date pair appears only once, keeping the row with the highest amount. Then sort by customer_id and purchase_date ascending and verify the final row count matches the number of unique pairs. Do this for the sheet named Q2_sales and report how many duplicates were removed by Friday.

Before I hand this cleaned file to the revenue team, make it obvious what you removed and why. On the Q2_sales sheet, show the number of original rows, the number of unique customer_id+purchase_date pairs, and list the top five removed rows with customer_id, purchase_date, and amount. Add a one-line note at top saying I kept the highest amount when duplicates existed.

We exported Q2_sales and I see repeated customer_id and purchase_date combinations. I am worried removing rows will drop valid variant transactions. The finance lead expects the highest revenue preserved, but operations say keep the earliest entry. Which rule is most defensible given revenue reporting, and what exactly should I do now to pick and document the kept rows so both teams can review?

Every monthly export shows the same problem: duplicate customer_id and purchase_date pairs that waste 30–90 minutes to reconcile. I want a repeatable habit so the imports are consistent and auditable. Recommend a concrete checklist and one formulaic step to run immediately on import that removes duplicates reliably, a short note to leave in the sheet header, and the team member who should sign off after each import.