The phone number you called is not avast but a third party that only handles certain things on behalves of avast and billing questions isn’t one of them.

The auto-renewal will take place on the day (or very shortly before it) your current subscription will expire, which in your case will be around this time next year.
You can disable the auto renewal anytime you want > https://www.avast.com/faq.php?article=AVKB24