It doesn't matter if you use avast or not.
You have bought a subscription and unless you end it, you have to pay for it.
It is just like magazines.
It doesn't matter if you read them or not.
As long as the subscription is there, you need to pay.
avast does not deduct money without a prior notice.
avast is sending at least 2 mails before the automatic renewal takes place, giving you enough time to disable the auto-renewal.
If you don't read them or are using another email address there is nothing avast can do about it if you haven't changed it/have let them know.
https://www.avast.com/faq.php?article=AVKB126