Adding a hostname to an existing UCC Certificate...

We purchased a Comodo UCC SAN SSL certificate through gogetssl.com. I could swear that when I prepared the CSR that I included mail.domainname.com, autodiscovery.domainname.com, exchange.domainname.com as well as the same names with .local as the suffix. My certificate is only good for domainname.com and domainname.local. I asked gogetssl.com if I could add servers to the certificate and they said that I would have to pay to add domains. I don’t want to add domains, I want to add hosts. Can I do this directly through Comodo? If so, what would the procedure be?