āThis submission does not meet AudioJungleās commercial production (recording/mixing/mastering) standard, and its commercial composition/arrangement standard either, unfortunately.ā
In detail, what are the reasons for you?
https://soundcloud.com/iceshine/creative-imagination-preview
Its very good. only broblem with whistle, i mean not very realistic. Maybe because of that was reject,
Recommended to read this article. Problem, that i wrote, have described in the 3rd item in this article.
Good luck mate 
If you make your track too loud, it will sound bad. do the mixing at different volume levels.
https://audiojungle.net/item/upbeat-fun/19504078
Well, Iām undecided if I have to keep adjusting the mix starting from āthe whistleā or give up.
The reject comment criticizes both composition and mix/master, and, categorically add "unfortunately we have not found the quality standard required to move forward and you will not be able to re-submit this item again."
It seems to mean ādonāt waste time, youāre not capable for this trackā.
If there was any potential, they would have responded differently, or not? Iām very frustrated! 
What is it preferable to do in these cases?
(forgive my poor english)
New track write.
I wouldnāt take too much notice of the reasons given for rejection - itās just a standard cut and paste piece of wording and not specific to your track.
As has been said, main issue is the whistlling. The rhythm could possibly do with a bit more variation and lightening too.
For the whistling i think avoiding the large glissando slides up and down would help a lot. Just use separate notes without legato when doing large pitch changes.
Iāve noticed theyāve toughened up on not accepting resubmitted tracks that were originally rejected, but do think that this track has the potential to be a very commercial if you spent some time reworking things.
This way of doing, with no communication between sellers and audiojungle platform, doesnāt help both to improve.
Anyway, thanks for your suggestions!
Yep, I agreeā¦ I wouldnāt yet give up though. Try to fix the whisteling and give it a go one final time
