Offloading issue

I have an app on my phone that needs all the information associated with it removed. The information needing to be deleted is the user required data (name, email address etc) in order to be able to create a NEW account within the app.

The app in question is the Insight Timer app that now has a default user verification window upon opening. Once I offload the app and delete app, then go to the App Store to reinstall, my email address is still in the App upon opening.

Insight Timer Support has been working with me for 4 days trying to figure out how to get this rectified. I NEED this app. I need help to figure out what can be done.

Please help!