So I just received my brand new slash 4x4 and as I was going to put AA batteries in to my radio they just kept falling out. I noticed they didn't fit and I had no clue as to why. It's like there is a piece missing in my radio and I do not know what it is. The batteries just slide around. I feel like there is something missing in the controller. Shouldn't there be something there to connect with the batteries, on the bottom picture.