Contact them via Twitter, see details below as kindly provided by another CC member
Contacting Airbnb Via Twitter
Airbnb seems to have dedicated staff who monitor their Twitter feeds and I usually hear back from them within 5-10 minutes of posting my isssue.
Step 1: Log into Twitter
Step 2: Search for @Airbnbhelp and choose "Follow" them
Step 3: Send a Direct Message (DM) explaining your issue and wait for their response. They may ask for information such as your listing but always provide it over DM so it is not public.