Log in to Paper Tools and open your Profile. There you will see a button to cancel your renewing credits.
The payment processor I use insists on thinking in terms of “subscriptions”. A subscription is never required to use Paper Tools, you can purchase one month at a time and use only what you need.
You can also manage your subscription on the Paper Tools shop at: https://shop.papertools.ai/pages/manage-subscriptions
Enter the email you use with Paper Tools, then check your email for the link.
Once your renewing credits have been canceled, you can continue using the Paper Tools application until your current access period has expired.