Yes, there were many people who were victims of ponzi schemes, and loses their money. OP you better research on the background of the place you are going to invest on. Do not be mesmerize with their high exchange on small amount of you investment most likely they are the one who are scammers.
All you have to do is to research. Not just from once source, but try to get more about the history of a company that you are investing. The you have a conclusion to put investment there or not. Because at the end of the day, your investigation and legitimacy about a company would be the best source of facts to help you establish your conclusion. So before investing your money, you have to invest as well on doing a proper research.