I don´t know what else to do more than to open a ticket at:
securepaynet.net/default.aspx?prog_id=simple
then click "faq"
then click the "Email support" link.
Also, please do not bump threads.
Ok, please try to go to the register site mentioned in your initial post, then click support and then click "6. How do I retrieve an authorization (or EPP) code for my domain(s)?" in the top 10 questions.