Shortmax Weekly Subscription Cannot Cancel And Charges Continue

I have a weekly subscription with Shortmax that I am unable to cancel. The app does not show any option to cancel, and Shortmax itself does not appear under my subscriptions in the Google Play Store, so I cannot stop the automatic payments from there either. This is my second week using Shortmax, and during this period I have been trying to cancel the weekly subscription without success. I contacted Shortmax customer service, but they only gave me the runaround and did not provide any clear or direct answer on how to cancel my subscription. My bank card is being charged 19 dollars every week for this service, and I currently have no way to stop these charges from continuing. I find this very worrying and inconvenient. I request that my Shortmax weekly subscription be cancelled immediately so that no further payments are taken from my bank card, and that I receive a refund for the period in which I have been unable to cancel despite my attempts. I also want my card details removed from their system after the cancellation.