I can`t cancel my account
I replied on your email too. As mentioned there, you are subscribed to LingQ Premium membership via the Android app and Google Play. To cancel subscription, please login to your Google Play account and cancel it there.
Here's how you can do that: https://support.google.com/googleplay/answer/7018481?co=GENIE.Platform%3DAndroid&hl=en
Hope this helps!