WooCommerce Support System allows you to automatically close tickets that are not updated by the user within a certain number of days.
Once the dedicated option has been activated, it will be possible to set the number of days of inactivity of the ticket, and the message that you want to send to the user to warn him that the assistance request is about to be closed.
It will then be possible to set the number of days to elapse between the receipt of the email notification and the actual closure of the assistance ticket.