Ok, so basically I applied a data validation over a cell so that it can't be more than 16. When this happens, a message appears saying that you can't do that. The problem is that I also assign a spin button to the cell, but when I increase the number with the button, and the number of the cell exceeds 16, nothing happens.
Do you also try to eat your cake and have it too? Seriously, without seeing the actual spreadsheet and cell you're describing, it sounds like you're just overloading that poor cell with incompatible expectations.
If you could upload a sample so we could see it, we could make more specific recommendations. Absent that, just trying to make sense of what you've written, I'd think you would achieve your goal by splitting up the conditions that need to be met, and/or the functions that need to be performed, into two or more cells. That way you could see more clearly what's going wrong, perhaps use a conditional format rule on one or more to highlight when boundaries have been exceeded.