@Sima85 if you're booking is more than two weeks away you should be able to cancel penalty free within 48 hours. IF you cancelled straight away.
It sounds like you didn't meet that condition, so Airbnb has retained their fee. This is nothing to do with the host.
All the ways of contacting Airbnb are listed in the Contact Airbnb post towards the top of the forum you are posting in 🙂