It can only be sorted out on the iPad. I would need a few minutes with you to fix it, but on the iPad.
I would need you to find the Settings app on the iPad and check what accounts are installed. The steps would be as above.
That's ok, I can post each step needed.
The home button brings you back to the home screen.
Press it and it brings you back to all the apps.
Settings looks grey and has a mechanical look.
Tap it and then on the left hand side swipe with the touchscreen to scroll the list up and down.
Look for Mail, Contacts, Calendars and tap it.
The list of accounts appears on the top right.
Let me know this so we can go to the next step.