I cannot find some of my previous purchased songs on iTunes Music Store? Lost?? Strange!

Hi,

I have lost many musics in the same album which I had purchased on iTunes Music Store.

I bought an album named "100 Supreme Classical Masterpieces: Rise of the Masters" about a year ago. It is a collection of classical music. It was a 100 piece of music but now I want to re-download it but it only shows me 15 tracks. I've checked it is not hidden. I've tried to search for it in iTunes Music and I found it. It is a 100 track album and it says that you've purchased this but in Purchase section only gives me 15 songs. Please help

Any idea?

Thank you.