My xbox 360 controller black thing that battery controller go in doesn't work?

I know it's not the controller, because I put new batteries and exchanged the batteries between the black battery things on the back and know for sure it's the black thing. I looked inside it and one of the silver things the battery goes on was under something else. I poked it and got in back into position but it still doesn't work. Anu suggestions? DO i need to buy another controller because of the stupuid silver thing in the black thing not working? Or would a rechargable battery pack fix it?