Mobe CWB L-XXL Boots not fitting? Help!

So I have an old wake board that a friend gave me a few years ago, and have been using it. It has Mobe CWB boot bindings on it that are labeled L to XXL size, however cant get anywhere close to getting my size 10 US foot into it. I have taken the boots competently apart, but cant seem to find any way to make them larger, as the inside lining is screwed down to the plate with only one setting, and there seems to be no way to make it larger. How can I make these fit, because I must be doing something wrong if the are labeled for l -xxl. Is there something like a spacer that goes between the mounting plate and the top plate that clamps it together, because this would rise the lining up higher giving more room, and I was considering making this with some wood or ABS plastic. Sorry I dont know much at all about wake boards. thanks!