You did give permission when purchasing a license.
There was the option to opt-out of auto-renewal but you didn't do it at that time nor later.
That means the auto-renewal will automatically take place and it doesn't matter if you have avast installed or not.
Why didn't you asked for help when you had problems ?
We would sure have tried to help you solve them for free !
You can not talk to someone about this.
You will need to submit a ticket:
https://support.avast.com
