I will refer you to a comment I made on this post. 
"adwaita" could be used as the "engine" component for your desired theme overlay. You need to examine the contents of the theme's component files to determine if they are just basic adwaita, or your chosen named theme.
If there is no theme directory by your chosen name found under
/usr/share/themes
then
- your attempt at installing the theme has probably failed, or
- you may have downloaded, but not installed, the theme bundle.
The only other option is that the them bundle is malformed and cannot unbundle properly, for your particular environment, possibly because your desktop was not a "programmed scenario".