Why can't I install Piano Level 9 - Beat Music Duel from the App Store?

Hello

So I'm trying to install an app.

It's called Piano Level 9 - Beat Music Duel.

I've been using that app for weeks and now I can't download it. It's very sad. Every time I try to download it it keeps saying unable to install the app is no longer available in the app store.

Help me please!!

[Re-Titled by Moderator]