Turn off Auto-Renewal in Avast Using the Customer Service Portal
1. Go to link support.avast.com/refund.
2. fill in the information with the cancel request.
3. It is important to use the same e-mail you have used during the original purchase.
4. Wait for the Avast Customer Service response to confirm the cancellation.

For more information: Avast customer support number | Avast technical support number