Over ten years ago I moved to the Netherlands without a single word of Dutch in my vocabulary. It was a steep learning curve as you can imagine. Now I can read, speak and listen to Dutch with relative ease, but writing...now that's a different story.
Grammar, spelling, syntax and phrases, they're all different and I'm sure you feel the same when writing in English rather than your native language.
When talking to someone face to face or on the phone they can already gain an impression of what you are like based on your voice or your body language. When you write all you have are the words and the way you put them together. This is why it is so important to do you best to make a good impression. Even more so when you are taking an exam.
This is why I'm here to help. I know what you are going through, let's work on it together.