Why do you crooks keep trying to bill me

Avast Free Antivirus / Premium Security
1

I have cancelled every subscription yet you crooks keep trying to bill me.

2

A little more information (excluding license/subscription number or personal information) would be helpful.
e.g. product you are being billed for, by whom billed, etc. ?

It sounds like you haven’t cancelled your auto renewal payment mandate.
Cancelling automatic renewal of the Avast subscription - See https://support.avast.com/en-en/article/35.

If the funds have been taken:
Refund request - https://support.avast.com/en-ww/contact/sales_refund If you haven’t got the Order ID, etc enter 00000000 and give as much information that you can to help identify it.