I subscribed to Scroll Viewport App and it was visible in the apps menu - that's where I could reach it from. After the Confluence got updated the Apps menu is empty, showing only the popular apps (slack, lucidcharts, InVision).
Where can I reach my paid app and use it?
Thanks,
David
UPDATE: I figured out - I was logged in with a non-admin account 
Admins, please delete this post, as it has no purpose, except for publicly showing my stupidity.