I fractured the screen on my iPhone 4, 2+ years old and the latest when bought so I bought a new phone but I can not get my previous purchases to download to itunes that were there 2 weeks ago. Changed apple id once and now it shows up when downloading.

I bought a brand new iPhone 4 as soon as it came out which was 2010 I think. No problems until two weeks ago. I fractured the screen on it so I am slowly losiong some functions like charge, touch screen ability and need to activate my new iPhone but I am having trouble with iTunes showing my full song library. I have 554 plus songs but some that will not update or download,. Two weeks ago is when this all began. I used to have a different apple ID but changed it after a few months for security reasons. Now when I try to observe my itunes library it only shows the most recent songs I have purchased,35. Not all, and there are still songs that it states it can not download because my computer is not authorized, I authorize it and it says it is already authorized. Then it gives me the old apple ID from years ago and I change it back to my new one, but this only causes it to do it over and over. I called apple and they said all kinds of mean things that my son or husband had been using my ID or account, of which is impossible because all purchases have to be password protected and I get warnings if anyone attempts to access. Also, their ID's are not my old one. Their libraries have none of my music. I do not home share but I thought that iTunes says you can use the music for households if you homeshare so I do not know why the person was so abusive but I am frustrated. So, any ideas? I was instructed to install icloud and did and it seems to me to be the culprit so I bought the stupid iCloud sharing manage,$25 yearly so that it automatically downloads your full library but no luck, still only shows the purchases I recently made with my gift card. This was suggested by the apple care expert. Can not update my phone until backed up, can not change phones until updated and backed up.