Try to reset your device and force quit the app
Reset
Hold down the sleep and home keys for about 20 seconds. When you see the silver apple, let go and let it reboot. No data will be lost.
Force close an app
Double tap the home button. When you see the app previews on the screen scroll sideways if needed to get the preview in question on the screen. Flick that preview up and off the screen to close the app. Single tap the home button or home screen preview to exit the mode.
If that doesn't work you can try to delete it and reinstall it. Also look on the reviews for the apps. You may need to change the sort from 'most helpful' to 'most recent'. It's a good place to see if others are also having the issue. If none of that helps, try to contact the developers of the app and see what they can suggest.