Hey @genshoyukawa, help's here.
We currently don't provide a 3 months trial for free. We either have a 3 months offer for 0.99 USD for users who have never paid for Premium before, or 3 months for 9.99 USD for returning users. Maybe you took one of these offers?
If the offer was provided by one of our partners, we suggest that you get in touch with them instead.
Let us know if there are any other questions. We're happy to help 🙂