@signal flare yes that is a possibility as well as a bad battery but we would need to see more. It appears as if there are some screws in the back and side pieces. Looking at the rim of the case it appears to be snapped.So running a plastic opening tool along the edge should release that after the removal of any screws.
Post some pictures of your own Rock box so we can see what you see and hopefully assist you further. Adding images to an existing question
When you are taking it apart take lots of pictures and create a guide for the next person that may have issues with it. https://www.ifixit.com/Guide/new it's pretty straight forward.