Step 1: Log in to your account at http://bandcamp.com
Step 2: Select "Tools" from the dropdown in the upper right corner under your account icon
Step 3: In the Reports section, select "Raw Data Report" and when selecting make sure to check payment details, items details, buyer details
Step 4: Pick a date range and select export
Note: To make sure you have all historical data, we suggest a date range going back to the creation of your Bandcamp account to today's date