Looking for an app that has disappeared

I have this app for Grammar, and I really like it now that I’ve got around to trying it out.  I liked it well enough to pay a decent amount for it, but it’s GONE.  It’s like it never existed.  I can’t find it on the American or Japanese iOS App Store.  I even emailed the developer and haven’t got a reply.

Anyone know where I can find this?
Edited: 2017-12-04, 12:33 am
If it's iOS did you try to "purchased apps" section? At least in iOS 10 it was still possible to download something that was no longer listed.

Otherwise your only hope was if you did an earlier backup.
Edited: 2017-12-04, 9:23 am
Without having checked, my first guess is that it's vanished from the app store because the developer never updated it to support 64 bit.

The devs seem to be these folks -- but their last blog post update was a year ago, so if the itunes link on that page doesn't work for your device you're probably just out of luck.
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