Re: Problem with English level
I would be interested to see what the "contextual errors" are so it's a shame they didn't let you know what they were. There are only a couple of hints in your first post which would have made me think you are not a native speaker:
1) The use of "highlight on". It should be "I asked them to highlight the incorrect areas".
2) Saying "That's when I thought of joining this forum". People don't just "think of joining a forum" out of the blue. I would have expected to see "That's when I discovered this forum and decided to join it in order to get some advice ..."
I agree with charliedeut's suggestion about posting in the Editing and Writing Topics section. Try not to post too much at a time though. Many of us, when faced with a piece longer than about ten or fifteen sentences, will think "No, I don't have time to do that justice" and we will go and finder a shorter post to deal with.
Remember - correct capitalisation, punctuation and spacing make posts much easier to read.