I think it’s quite hard to find out if someone you are following but he or she aren’t, right? Or perhaps at least I have this problem. Instagram is not like Facebook which require two way relationships whenever you friend with someone. Unlike Twitter, Instagram does not supply information if the person is following you back or you are not following your followers back.
The screenshot below was the output of the code I tried for my Insta. If you don’t want to jump to the coding part you might try the final product of the code here: http://sandbox.mahadirlab.com/instagram/ .