I'm only on the third chapter, but I am torn as to whether to continue on. You seem to have a very original story and one that has great potential to be a five star story, but... This is the part that no new writer likes to hear. I know, because I have been there. Clearly, English in not your native language. While the imagination that conceives a story, usually, transcends language and culture, idioms and colloquial expressions, often, do not.
Read the story now
There two paths that you could follow. One, write your story in you native language and ask a true speaker of the language that you wish to publish in to translate the story. Work with them to make sure that it is still your story; the one you intended to write. The other path that could help you is to avoid idioms and colloquial expressions to the extent that it is possible. If you must use one, to provide color to your story, then research that phrase very carefully before including it. Having fewer "colorful phrases", but having those that you do use be "spot on" will serve you better.