You can control what email addresses your customer will see on the Customer Portal to click and contact you:
Steps:
Go to "Settings" in the top-left (please note that you must be an admin of your Company)
Select "Emails"
Pick an Email Profile
You will see the option to turn on/off the email address visibility on the Customer Portal:
If the email profile requires the customer to be part of a specific customer portfolio, Kolleno will automatically select the allowed email address that this customer can view on the Customer Portal.
You can find more information on Assigning Customer Portfolios to Email Profiles.