What do I do if I bought my iPod from a friend and I never registered it and it got lost?

I bought my iPod from a friend and never thought to register it. A few days ago, I lost my iPod and locked it and put a message on it for whoever finds it to call me. I got an email from iCloud saying it was found in another town. I saw where it was and expected my call. No one called. It hasn't been online since. I went on Apple.com and tried to use their services for finding it by signing in and selecting my registered iPod but that is a problem because I never registered it. What do I do?