Almost anytime you have to funnel Poof balls down from a wide hopper into a small opening [without an agitator / sorter / indexer of some sort] you are going to jam. Period.
Funneling works well for some types of balls, but it only does so because the lack of a lot of surface friction on the ball. Pool or ping-pong balls would be good examples of this, as the surfaces of the balls will just slide past each other. But because of the compression and surface friction of a Poof ball, they would rather compress themselves than roll past each other.
No one said that this would be easy. And if they did, they were obviously refering to a little red button from Staples and not to FIRST. The fact that the Poof balls do not funnel down easily is just another design challenge.
If you need inspiration, I would suggust looking through CD-Media. There have been hundreds of pictures of robots uploaded so far this year, and I'm sure at least one of them used an idea that you might be able to "borrow" to suit your robot.