Shortmax Not Responding to Unauthorized Subscription Complaint

I am writing regarding unauthorised weekly charges for a Shortmax TV streaming subscription, which I access via browser and not through any app store. On 30 March, I noticed the first charge of about $20, and a second similar charge was taken on 6 April. These payments are appearing through Google Wallet, yet I cannot find any clear transaction record or subscription entry there that I knowingly accepted. I have never knowingly authorised a recurring weekly subscription for this service. After noticing the charges, I contacted Shortmax, but so far, I have not received any response or clarification about why I am being billed in this way or how this subscription was started. I request the immediate cancellation of this Shortmax TV streaming subscription and a full refund of all unauthorised weekly charges taken so far. I also expect written confirmation that the subscription has been cancelled and that no further amounts will be deducted from my Google Wallet.