@Joy5 Your account has definitely been compromised by a scammer. You will need to contact Airbnb right away. Also, you need to check your account settings for notifications and then change your password. Once a scammer gets into your account they change the notification settings specifically so you won't be notified if someone accesses your account from a browser you don't use. i have flagged this listing as an added precaution.
Here's how to contact Airbnb:
https://community.airbnb.com/t5/Tips-Tricks/Contact-Airbnb-A-Community-Help-Guide/m-p/16165/highligh...
The best and fastest way to reach Airbnb is through twitter @airbnbhelp. If you don't know how to use twitter, I will contact them for you and have them reach out to you.
The reason this happened is probably you responded to a phishing email that looked like it came from Airbnb but did not. If you need more help from me, just reply. I'm standing by to help you!
Clare