Call from a collector?

I got a voicemail message from a lady claiming I had written a bad check. She said that the file had been placed on her desk today. She ended the call by saying that I had been notified and that I could be approached at my work. I tried calling the number back and the message simply said "American." Then it said to leave a message for the extension I wanted (didn't have one). I tried to do a reverse phone number lookup and can't find anything. I'm petrified. I don't write bad checks and I don't know why these people would call me.