So you placed an order with us, got your puzzle in the mail, opened it up and started to use it. Shortly thereafter, a piece or many pieces of the puzzle fell out and you can't use it now.
Don't worry! It is more than likely that your puzzle isn't broken. These puzzles are designed to be tailored to each competitors different style and taste. As such, you are able to take them apart, adjust the tension to make them more loose or tight and reassemble. These aren't your parents' Rubik's Cubes.
You may need to grab a screwdriver and adjust the tension so it isn't too loose, which allows a piece to become dislodge from the puzzle if you turn it a bit inaccurately. This is referred to as a "piece pop" in cubing.
After that, you can reassemble the puzzle again and you should be good to go. Some puzzles will be more difficult to reassemble than others. Consider this an added puzzle to your existing puzzle. It is a good skill to have to be able to reassemble your cubes. If you are going to use these types of puzzles for any real amount of time, you are likely going to encounter it.
Good luck!