Hello Zeheng,
If you still haven't been able to contact the landlord you could contact Airbnb support and ask them to try. I've done this a few times on Twitter.
Type "contact airbnb" in the "Search the community" box on these forum pages where you posted your question. Scroll down a little in the list of suggestions that appears and click on the "Contact Airbnb: A Community Help Guide[UPDATED]" one. That lists phone numbers and ways to contact them via Twitter or Facebook.
Steve.