A campaign sends one AIDM template either to cancelled payments (after a delay; a matching purchase stops it) or to purchases (automatically after each new purchase, or once to past purchases in a date range).
Every purchase webhook, whether or not the buyer cancelled first. Reminder sent = a cancel reminder for that course reached them before they bought. Export uses the filters above.
Staff see every page, read-only. Admins also manage campaigns, export CSVs and manage Staff accounts. Super Admins also manage Admin and Super Admin accounts. Nobody can change or remove their own account here (use Account).