how do you take the battery out of blackberry classic 6?

You sound like you're new to BlackBerry 10. It's not BBOS7, where pulling the battery to fix problems is the norm.

Since your question is email related:

1. You can try reseting the Hub: Go to the Hub screen, swipe from the top-right to the center of the screen five times. The Hub should reinitialize.
2. You can turn off/on the device. Rebooting BB10 only takes about 1 minute, much faster than BBOS7.
3. You can hard reset by holding the Volume Up and Volume Down simultaneously until the device reboots and you see the BlackBerry logo.
4. You can remove and then re-add the email account that's giving you trouble.