Charged for Trial of an App Which I deleted

I looked for an app from the store to recognize types of plants. Although I used it twice, I would not need it consistently and deleted the app. I noticed on my checking account that Apple charged me for the app to the turn of $31.89 I would never pay that for an app which I deleted. I want a refund. There was absolutely no notification that the subscription was beginning which is lawful. Therefore, not only do I want the $31.89 refunded but I want a complete cancellation of this app.