Single Page Deindexed?

Does Google ever deindex a single page from a website? My site had been ranking page 1 for a profitable keyword, but recently dropped to page 2. When I checked, I noticed that instead of the page I had targeted the KW with, it was my main site homepage that was ranking instead, and the page I wanted was nowhere to be seen. Checking site:mysite.com "keyword" doesn't show my page either. To top it all off, I got a message in WMT a little while back saying they suspected that my site had been hacked, but when I look for details, WMT now says there is no signs of hacking.

I tried resubmitting the specific page in question, and it showed up in the site:mysite.com "keyword" search, but did not rank. It's now disappeared again.

Has this happened to anyone else? Any suggestions for how I can fix this? Is there possibly a competitor that is trying to sabotage my site?

So I kept poking around in WMT and tried the "Fetch As Google" tool, and the page shows up more or less fine. But when I go to the "Data Highlighter" tool to mark up the page with structured data, it redirects my page to the homepage again. I know that "Fetch As Google" does not follow redirects, but manually visiting the page isn't redirecting me either. Still very confused as to what could be going on.

Any advice would be appreciated.

Remove the website from your current webmaster tools account, and link it to newly created one, voila problemo solve.

totally possible that this happends.

use this query online site:yoursite.com

then find the specific page of your website and see if it is indexed.