In section Available Mailers of Scotia Online's Bill Payment > epost, I found COSTCO WHOLESALE, so I called 1-800-4SCOTIA for confirmation. The agent told me that it is indeed possible to pay Capital One COSTCO MasterCard bill via epost.
When I entered my 12-digit COSTCO membership number and my postal code to Add a Mailer, Scotia Online came back with error message "The values entered are invalid". So I tried to enter Capital One COSTCO MasterCard number, but this field accepts only 12 digits. I called 1-800-4SCOTIA again for help. The agent told me that it is not possible to pay Capital One COSTCO MasterCard bill via epost, and that epost is only for paying membership by non-MasterCard users.
So, please change the entry in section Available Mailer to "COSTCO WHOLESALE (MEMBERSHIP FEE PAYMENT ONLY)" so that COSTCO members in Scotia Online as well as 1-800-4SCOTIA agents would not get confused?