Sometimes, I've noticed that I too have missing information when I upload a CSV list from an Excel worksheet. I then realize that when I saved to CSV I need to choose CSV (Comma Delimited). In my Excel I have 3 CSV "save as" options:
CSV (Comma Delimited)
CSV (MS-DOS)
CSV (Macintosh)
I've noticed that if I don't save as Comma Delimited, that there are funky things that happen to the upload.