How to cancel my subscription?

Hello,
I’ve an Avast Premium Security subscription on a device that I don’t use anymore and I would like to cancel it.

How can I do that?

At first there was no account linked to this subscription, I tried to connect with my email to cancel it from the website, but it doesn’t appear in my account.

I tried to send email to the support but they cannot help me.

Any idea?
Thanks

Did you use this: https://support.avast.com/en-ww/article/Account-unsubscribe/#pc

Hello,

Many thanks for your answer.
I tried but my subscription doesn’t appear in my account.

Is it possible to have a subscription linked to a computer and not to an account?