Do you want to cancel your Avast subscription? You don't need the services any longer. How do I cancel my Avast subscriptions? Here are the instructions to cancel:

First, sign in to your Avast account (use the link,
Choose the My Subscriptions tile.
Select the subscription you want to cancel.
Click on Unsubscribe to cancel subscriptions.

Check the status turn to Expire when the subscription is canceled. However, you will use the services till it the validity expires. Mostly it switches to the free version. You can also request help from Avast so:

Click on the link,
Scroll down to "Request help from Avast."
Select your reason from the drop-down list.
Enter the order id, name, and email id.
Click on start chat.
After this, you will be able to remove your subscription. Visit the official website.