Open Settings → Support, select the active ticket, enter your response in its reply field, and submit it.
Keep all information about one problem in the same ticket. Include new error text, the result of requested tests, and any change in symptoms. Do not include main passwords, Vault app passwords, Mail client passwords, backup codes, or payment-card details.
Reply from the Support page even when you received an email copy of the staff response. An ordinary reply to that email is not added to the ticket conversation.
Close the ticket when the issue is resolved. A closed ticket remains available for reference but cannot be reopened through the reply form.