So I received my email from Amiga Kit with my serial# with the instruction to register said serial at the following link.
https://www.amisphere.com/download/a1222plus_early_adopter.php
Do you have a login to AmiStore. If you do, that is your amisphere login you should be using with this link. Not your AmigaKit login.
I did manage to get mine registered and was able to sign up for the Tabor program but I'll admit the process was a bit confusing and I don't quite recall all the steps I had to go through. As I recall when I used the above link and logged in with my AmiStore login, it told me I had to register the AAA product first. I believe I then went to AmigaKit and logged in with my AmigaKit login which I had created when I placed a previous order. I then looked at my order history and saw that I could register the AAA product. Once I did that I could use the above link to sign up for the Tabor Early adapter program. At least that's the best I can remember it. I might have forgotten a step but that's the general process I used and was successful at.
Did you try clicking the link in the email you received when you first ordered the AAA product?
After ordering you should have received an email with the subject "Order Process". This link should take you to the AAA order information.
Hope something in this reply helps. Hopefully AmigaKit will see your post and help you out if this doesn't work for you.