Hi itay,
Sorry for the inconvenience.
Please follow the steps below to update the theme.
1. Go to Appearance -> Themes
2. Active another theme & delete the hostwhmcs
theme
3. Click Add New -> Upload Theme
4. Upload, install & activate the latest version of hostwhmcs
theme
Moreover, you could try this Envato Market Plugin http://envato.github.io/wp-envato-market/
Best Regards,
ThemeLooks Support Team