Secure Browser Pro 30 day free trial

I started a 30-day free trial of Avast Secure Browser PRO and entered my card details to activate it. However, the trial does not appear in my subscriptions in my Avast account, and I cannot find any way to cancel it online.

I want to cancel the trial immediately to ensure that I will not be charged when it ends on November 20. My card currently has no money, so I am concerned that if Avast attempts to charge it, the transaction might fail, and I want to make sure I am not left with any issues.