Wrongful termination??

Hi, live in California. In August of 2007 I was put on a final warning for attendance. I was terminated in January of 2008 because according to my boss I had called of sometime between October-December of 2007. So the hours missed according to my boss is what determined my termination. From August 2007, when I received my final warning, to the day of my termination I know for a fact that I didn't miss a day or was late for work. I had perfect attendance. When I was terminated my boss never showed me any proof or some kind of paper stating exactly what day I called off on. This has left me defenseless. I appealed the termination and right now it's being reviewed. So my question is, can someone be fired without being shown some kind of proof?