Keywords have disappeared from GOOGLE search

I regulary monitor how my school's keywords are performing in Google search. I was aghast to see a couple of days ago that we no longer rank for any of our keywords. Despite not ranking anywhere, our website is still live and if I key in a URL, the page displays (with one exception). Here is our website address: www.avse.edu.vn

I am looking for someone who can fix this problem pretty much immediately.

Cheers, Peter