Shortmax Subscription Cancellation and Refund Request

I recently subscribed to the Shortmax service via their app and was charged 10.99 on my bank card yesterday. However, I never received any email confirmation of the purchase, the subscription does not appear under my Apple/Google app store subscriptions, and I am unable to cancel it through the app. Because there is no visible subscription record on my side, I cannot manage or terminate it myself. When I tried to contact Shortmax, I could not find any phone number, my emails have not received any response, and the feedback button within the app is not clickable, so I am effectively left without any support channel. The only evidence I currently have is the 10.99 Shortmax charge that appears on my bank statement. In light of this, I request the immediate cancellation of my Shortmax subscription and confirmation that no further charges will be taken from my account. I also expect a clear written confirmation of the cancellation so that I know this issue has been fully resolved.