Upload new version and make notes for the editor explaining what has happened, when new one is accepted then and only then do you disable the original version.
You need to make sure your monitor is calibrated correctly so you see the colours and levels as they would appear when printed.
There's a chance you are calibrated correctly and the "other" monitor you viewed your image on is not calibrated correctly. Either way when submitting pictures with white or black/dark backgrounds it's always worth using the level slider in photoshop to push your image to the max light and dark, this is a good way to see blemishes or other issues in your background. Pretty sure some if not all reviewers may do this to review our images but this is just a guess.
Canon L 28-300, Canon L 24-70, 50mm prime f/1.4, 2 x Canon 580EX II F...