Cancel ShortMaxTV App Subscription Immediately

I am using the Shortmax drama mobile app on Android and, despite multiple attempts, I am unable to cancel my subscription. The subscription does not appear under my Google Play subscriptions at all, so I have no option there to cancel it. Nevertheless, I have been charged $19.99 every week since around 04/05 in Michigan, United States, and these payments are being taken from my credit/debit card. I have repeatedly emailed Shortmax to request cancellation and have clearly explained that the subscription is not visible in Google Play. In my emails I have also provided exact dates and my UID so that my account can be identified, but I only receive automated replies telling me to unsubscribe via Google Play, which is not possible because the subscription simply does not show there. The charges have continued for several weeks despite these explanations. With this complaint, I request that Shortmax immediately cancels my subscription, stops all further charges to my card, and ensures that no additional fees are taken in the future.