This app is the worst thing that could ever happen, it's messed up my Gmail beyond repair. I honestly don't understand why it gets promoted when it fugs with your emailbox without a way to ever go back!
I've spent 3 hours yesterday sorting through my "all mail" folder and moving things back into the "inbox" by hand, going through over 10000 mail messages. And still, everything is screwed up -- if I use the Gmail app, I can actually see all the email in my "inbox", yet when I use the native iphone mail app, the only thing that it loads into my inbox are messages that are from december or older, i'm not able to see any messages from the last 3 month. Sure, someone could argue that it's a gmail issue, but point is i never had this issue until this stupid app came in and moved everything around without a way to go back.
I'm beyond frustrated with the developers and the app, it honestly is the worst thing that could ever happen to your mail.
I'm now testing out moving all my inbox gmail over to icloud to see if my phone will load the complete inbox and that may be the only way to get my mail working again -- to actually switch to another mail provider!
Read the reviews online and you will see many un-resolved issues with this app screwing up your inbox from multiple other users. This website honestly should stop promoting such an aweful app.