I opened the app and decided to give the premium version trial a shot, especially since it said that the app would send a reminder in 5 days and not charge me for 7 days. Well guess what?! Not only did I get charged 19.99 right away, it is not listed as a subscription with Apple so when you hit cancel subscription in the app you can’t because it’s not listed under the subscriptions in your Apple account. It is listed as a purchase - and I can’t request a refund with Apple because it’s still showing pending (I am assuming that it will until the 7 days of the “trial” are over, at which point they probably think they can argue that you’ve had time to review and decide to cancel if you wanted too). I have put in complaints with Apple, will update if anything changes.
I’m sorry to hear that you are not happy with the purchase. On the paywall you have to option to select a plan (monthly, yearly or lifetime). In your case lifetime was selected. This isn’t a subscription because you only pay once. I’m not sure if you can issue a refund. At the moment I can’t do much. You are fully in the hands of Apple. If you have feedback about the app please let me know.