If it's an Outlook account, go to Settings - Mail, Contacts, Calendars; tap the account and then select "Mail days to sync". There are a few options to choose from. I've set mine to "Never", which means my emails will stay on my iPad until I delete them.
If the emails reappeared the first time you deleted your account, they'll be there again after you've done this once more. They're located on a server, and only sync to your device.
Try "refresing" the Calendar app. In the app, tap "Calendars" at the bottom, in the middle.
You'll see a list with all the calendars you use in the app. Tap on it and drag it down. A spinning wheel will appear, showing that the app is updating it's entries. When it's gone, tap a date in the app somewhere to make the list disappear, and look at your entries once more.
You can also see which calendars are enabled in your app, and check mark those you need.
Hope that helps.