InsTrack for Instagram for Android

I downloaded this for IG and it's asking me to login via FB. There's no other option. Is this a glitch? Or does this no longer work for IG?

I *CANNOT BELIEVE* this is a free app. A few things I wish I could use it to do -- * follow private accounts as competitors -- mostly just so I can keep an eye on the engagement of my private account in contrast to my public/business account -- I post similar things on to each as an experiment and see different engagements but I am curious why -- this app may be able to help me! * I am also looking for a follower tracker. I have noticed my follower count fluctuate significantly and I cannot pin down a reason why -- I suspect they are ghost accounts that Insstagram is cleaning up -- but without a way to compare my list from before vs after I cannot determine if the follower's account has been deleted or if they have blocked me. (to determine if the blocking is in effect I suspect you would just submit an http request without providing session information as a non-logged in userr to see if the account exists with unauthenticated user). Otherwise, wow ... this app is the BOMBDIGGITY! I've seen some other web apps that are charging GOBS of money monthly for not even the similar viewing.... I guess I would also ask for the possibility to export graphs -- and perhaps they could export the data as CSV or Numbers format that would allow me to customize the report or share without having to take a screenshot -- but I'll take what I can get for now! INNOVATTY! KEEP UP THE GREAT WORK! YOU GUYS ARE KICKING ASS! I'd be happy to pay for features -- and I am wrong in assuming this is a free app? I've not noticed any in-app prompts for licensing....