Question about Microsoft 365 Family

I also had the problem, this online portal for the keys seems to have some kind of problems with some e-mail addresses. I have already contacted Techdata who are responsible for the portal and never got an answer. But you can write an email to Digitec or call them, they can send you the key or the activation link to another email address. If that doesn't arrive either, they can give you a credit note and then you buy the box version.
You can also reach Digitech via the chat here on the site.