My P-Chem class was like that. If you had old copies of the tests, you were OK. I didn't. I got a D. Then the next semester, everyone was scrambling to get copies of the old tests, and most people got 1-2 years worth of old exams. After I failed the first exam (due to the same circumstances Dude described), a friend of mine who had graduated the year previous visited town again. She heard me complaining, and when she came back through town next week dropped off SEVENTEEN YEARS worth of old exams of this professor. She had the connections and just handed me this gigantic binder of old tests. Needless to say, I was ecstatic--and I salvaged my grade. I got a B+ since I had failed the first exam, but that was fine with me--I kicked everyone's ass on the last few exams and laughed about it. The sad thing is that I didn't learn anything. I learned more studying, but it wasn't rewarded--that is the big problem with larger universities where professors aren't checked to see if they are teaching and the university only cares about research.
Sadly, you can't demand your money back. The most you can do is complain about the professor, but usually that doesn't do anything unless he doesn't have tenure yet.