I have to tell you that the points really doesn't matter that much as long as you've passed the 80 score line. And the materials you sent through email probably isn't what cause the refusal, because I did the same thing and I didn't have much information to provide them.
Language may not be the problem because you must have been much more careful when you write your application.
From what I see what they really care about is whether you can bring the skill and knowledge they need and the local ppl lack of. So your industry matters. And your essay matters (you have to tell them why you are unique and why they need you).
You can go over your materials again and ask yourself the same question.
And if you really want to try it again, go ahead. It is free anyway.