Q: songs not shown as "Purchased" in store

where do you find "hidden purchases"?

i don't see that any where.

btw, the following did not work for me-

4. On your Account Information summary, scroll down to the "iTunes in the Cloud" section and click Manage.

5. Choose a content type by clicking Music, TV shows, Apps, or Books from the top.

i don't get that itunes in the icloud button, so i can't choose a content, etc.

The same problem here. 

I had the same experience and nothing worked for me including the official Apple Support.

In the future, if you want to put music into iTunes, buy the CD from a shop and read it into your library.  iTunes is not reliable and Apple is not helpful at all.