Same issue, no response. I have opened four chats with Adobe's support and it is like this is a new problem to them. No end in sight as yet.
Update:
Here is what I did, I downloaded Adobe Gigtal Editions to my PC, then I checked under help/authorizations and found the UUID, some long string of numbers. I gave that the rep in the digital editions forum and in two seconds I was good to go.
Let me know how it goes. very frustrating there for a minute. Seems like thay can't always find you by email, so the UUID is the trick.