I have hosted a guest who did not want to stay any longer and I offered a refund after one night stay. That was 4 nights minus one night. I even transferred cleaning fee to their account privately.
However, I never got paid from Airbnb for this one night + cleaning fee and I feel that they cheated me. The guest has left on January 7th, so it is more than 10 days since they left...
Airbnb is impossible to contact...what should I do?
Hate to say it but it sounds like a scam. You should have been paid the full amount approx 24 hours after they checked in. Then they should have amended their reservation and Airbnb would have taken care of refunds. You should never transfer money privately to a guest / that should be a huge warning sign.
contact Airbnb via Twitter to see if the guest made any payment. Search for Airbnb Help on Twitter