What do you man by not sharing?
If they do not appear in your library, they are probably hidden. To unhide them:
1. Go to the iTunes Store.
2. Click on "Account" under "QUICK LINKS". It should be the first button on the right-hand side of the page.
3. Scroll down to the category titled "iTunes in the Cloud" and click "View Hidden Purchases".
4. If you want all songs to be unhidden, click on "All Songs" on the left side of the panel and click Unhide All at the bottom-right side of the panel. You can also select individual songs or artists by the other tabs at the left.
If they are just stubborn songs that will not download even after clicking on the "Download" button, I can't help you. I will look into it.