Try deleting the app via your Settings app. To do, go the your Settings app, press on the General tab and then press on the Usage line. Look for the app that you're having an issue with (if it's not showing in the list, tap on the "show all apps" line.
Once you've found the app in question, press the line and, once you've been taken to the next page, you'll see a line where you can delete the app. Choose to delete it and it should then be gone.
Then, if you wish, you should be able to download it again from the AppStore.
Hopefully this helps.
Marilyn