Where to get a refund

[ScienceofSpock]

I have been using this app for 3 years. I have to restart it every 2 days or so, because it will just stop sending for whatever reason. I renewed my subscription for a year in December (Because as terrible as this app is, it's the only one that forwards SMS the way I want).
Now, the server has gone away, and the app is no longer listed on the play store, either for download or in My Apps. I paid for a year, not 3 months. What do I need to do to get a refund?

Note: I am putting this here because there is no contact option from within the app, the play store listing no longer exists, and the damn server is gone. This is literally the only way I can get in touch with the author.