Commision and Rate Plan

Dear Booking. com,

1. We would like to help our guests waive the cancellation fee. However, we would also like to know if we still gonna be billed on your commission when guests get full refund?

2. How do I know if our guests reservation is Non-Refundable because the promotion we listed, the rate plans option is "All rate plans" ?

Looking forward on your response. Thank you