If you're using a category axis then a
rangePaddingHigh value of 1 should be sufficient, as the value is in data terms, where 1 is the space between each category. Please could you clarify what value you were using in the screenshot above?
You may need to adjust the font size in order to fit all the labels on the axis.
If you can show us all the code you're using to set up and style your chart, or even better, if you could provide us with a working sample showing your issue, then we should be able to help you. (If you prefer not to make the code public then please feel free to email us at email@example.com).