https://www.avast.com/faq.php?article=AVKB126As info:
avast sends at least 2 mails before the auto-renewal takes place.
You could have disabled it before it did.
When buying the subscription, you have chosen the auto-renewal.
Perhaps you forgot about it or can't remember it, but you gave permission
The "standard" paid version is the pro version.
It is the smallest paid version.
It doesn't matter if you still are using avast or not.
You have bought a subscription and unless you disable the auto-renewal it will continue.
Just like with a subscription on a magazine, it doesn't matter if you read it or not.