Since Instagram launched the archive feature- any trolling as it relates to this platform can be easily moderated. Simply (temporarily) archive the piece of content and moderate comments (block users) and un-archive the content. As far as people trolling the # in which your promoting your campaign-unless the content violates community guidelines there isn't much you can do- I would say from experience- this doesn't as often as you'd think.

If I had more specifics about the campaign I could suggest more-- good luck!