Double-check that it is not in the IKPM (the IK Product Manager).
If it is nowhere to be found, then please contact
Sales/Account Support, via here. There is a link at the top of the Search FAQs page to a Support form. Sales Support can look at your Account and see what's going on.
Response time normally is within 2 working days (US (East Coast) Business hours, generally), but in the current circumstances please allow some more time.
You should indicate that you wished to use AT5 soonest as you are considering the upgrade to AT5 MAX, at the introductory price. But you cannot do that as the Serial number was not in the order acknowledgement email and is not yet available. Support would, I hope, be sympathetic.
Administrators and Moderators here cannot access your Account.