Did you recieve an email the day after your guest checked-in with the subject title "Payout of $000 sent"? I am also hosting long-term, and I have always recieved this email on the 22nd of each month (my guest checked-in on 21st). I've set my payout terms as Bank Transfer, and the money usually arrives in my account within 2~3 business days of recieving the payout notification email. I can also see a list of all my transactions under Transaction History. (Date of payout, type, details, amount)
I think you need to identify what exactly your problem by checking to see if you have accurate information put in for your payout method and also whether or not Airbnb has issued the payout or not. Good luck~!