@Nima81 Your listing is not currently displaying the auto-reviews indicating cancellations, so it appears that either you haven't cancelled the bookings or Airbnb has granted you a pass.
If those bookings are still active, I strongly suggest you go ahead and honor them. The penalty is not just the $50, but also having those dates blocked so that you can't rebook them.
If you've been lucky enough to get off the hook, PLEASE pause your listing while you take the time to learn how the calendar, pricing, cancellation policies, and other features of the platform work. The biggest mistake you made was to take your listing live before educating yourself on the basics. But by the time your first guest arrives, it's your job to be a relative expert on this stuff.