The API was shut down and the app removed from the App Store.
Bellbot may be a useful alternative.
You can trigger your Bell's ring URL with any cURL-like client.
$ curl https://api.lilbell.com/v1/ring/PUBLIC_KEY
And, you can do more with our API.
View the API Docs
Email us: firstname.lastname@example.org. We're on twitter: @smileslaughs #LilBell.