Please email email@example.com and we'll try to help you. If you're on Google Play, we can give you a link to download the game directly from us. We unfortunately cannot do the same on iOS, but we can try to get you to a good state from which to attempt the download again.
(Please note that download issues aren't a sign of poor software from us--our app hasn't had a chance to do anything until it is downloaded and installed! The app market and your device handle the download and installation.)