It is inadvisable to post your email address on a public forum, unless of course you like spam.
Cancelling automatic renewal of the Avast subscription - See
https://support.avast.com/en-en/contact/ and use the Refunds, cancellations, billing, payment, or license issues option and then the I want to unsubscribe. Click next and enter your details, if you haven't got the Order ID (as you say), etc enter 00000000 and give as much information that you can to help identify it.