iTunes- Why won't half of my music library install? Why is my music corrupted? And where did all my songs in the cloud go?

Alright there are multiple aspects to this problem.

Back in February of 2013, I bought the album "Goodbye Lullaby (Deluxe Edition)" by Avril Lavigne. I have 12 albums that I have bought through iTunes throughout the years by her. I had an iPhone 4S and did not update to iOS 7 right away. Later in October I got the new iPhone 5S and already came pre-installed with iOS 7. Somehow, (and I don't know why or how to fix it) a bunch of my songs (again purchased through iTunes) in the cloud are either hidden or erased and I can't seem to download them. When I received my new phone, I downloaded all the songs that were in iCloud. However I noticed that a few were missing. Then a few weeks later I saw that a lot was missing. I had a total 1,497 songs in the cloud, and now it has been reduced to 701 songs. That's about half of the songs that I have spent from $.99-$1.29 on music through itunes since 2004.

Fast forward to November 5. Avril Lavigne (big fan) released her new album. I pre-ordered it back in Septemeber. Normally the day an album is released I go to the album and pressed the cloud with the down arrow. No problem. However when I went to download this album, all it said was that I purchased it- no cloud with arrow, no nothing. I figured that it was in the cloud so I check under the purchase category in the iTunes App on my iPhone 5S. Again, no luck. Somehow when I logged on to my MacBook it downloaded a copy of the record on the computer. (That's fine. As long as I have the music...)

Then another problem springed up. I saw that Goodbye Lullaby was no longer on my phone, however it was in my iTunes library. I tried removing all of my music off the phone. Then ANOTHER problem came up. I unchecked the box saying "Sync Music" on my phone, and pressed sync. Then for some reason it automatically checked Sync Music, and all the playlists on my computer. I did this process multiple times. I updated iTunes, I reinstalled it. Restarted the computer- Nothing. So not only half of my songs are gone from iCloud, my music that is on iTunes is NOT syncing into my phone. Plus I can't take the music off my phone without iTunes checking the Sync Music boxes again.

the 3rd (and last) problem I have is that the music that did install in the sync became corrupted. So when I went to play them, the Music app would skip over them and then delete them instantly. One full album I had just went in a loop and changed songs lightning fast and then when I exited the album, it was delete.

Please let me know if anyone else has any/all of these problems. I will call Apple to straighten all of this out- and I might have to schedule an appt. at the Genius Bar at the retail store (which is an hour away so if I can get this problem solved here or over the phone that would be great)

Thanks

Duncan.