The app keeps crashing!
Then it is very likely that your copy of the app has been corrupted for an unknown reason (it may have happened during the initial download of the app or at a later stage).
To fix the problem you have to reinstall completely the app.
So here is the procedure:
1. Just in case, turn your iOS device off by pressing the top button for several seconds until you see the message "Swipe to power off". Swipe so it does turn itself completely off. Then turn it on again by pressing the same button for one second. This is the same thing as rebooting, sometimes it helps.
2. DELETE the app from your device.
3. DELETE the app from your iTunes apps collection.
4. Download the app again from the App Store. You will have to enter your iTunes password but you will NOT be charged, because Apple knows that you have already purchased the product. Downloading again is free of charge. You can download directly from your device if you want (it's generally more convenient) but you can also use iTunes and then sync your device.
The steps where we ask you to delete the app are important because that's how you get rid of a corrupted download.
If the procedure does not solve your problem, please contact us by email at firstname.lastname@example.org