If nothing was unclear or difficult, say so. Skip questions about steps you did not experience; use not applicable where appropriate.

Which invoice item needed explanation?
Where did you look for billing context?
What description would make the charge clearer?

Author notes / illustrative keys where applicable:
1. Use this answer to locate the part of the experience that needs explanation. The example issue to investigate is: customers confuse billing period with payment due date.
2. The source customers consulted shows where billing explanations should be discoverable. Compare those locations with official account guidance; searching elsewhere does not establish that a charge was incorrect or unauthorized.
3. Turn the requested improvement into a testable next step. One illustrative action is: label billing period and due date separately.