Welcome to Android Central! Where are they being listed as unknown? In the People app? Or elsewhere?
Are the contacts saved to the Phone Account or to your Google Account? This doesn't necessarily answer your question, but I would just make a plug here to encourage you to save your contacts to your Google Account. They are much easier to edit on a computer browser at google.com/contacts, they sync automatically with your phone, and if you ever have a problem with your phone, you know all of your contacts are safe in the cloud.