Empty app with surprising charges

I have downloaded this app to track my polyphasic sleep pattern, because it seems to be the sole app to do this. Right on the first minutes, I have noticed it was nothing else than a clock for you to see your own polyphasic plan, but nothing else that worth a comment. No problem, I didnt pay a dime for that... After a few days, I have received a charge of 5 dollars for this app. WHAT?! Does not waste your time (and money with this).

Filipevsm about Smart Sleep Polyphasic Planner, v1.1