I have the same problem. Two years ago it was possible to call the hotline or to write an email and adobe would reset the account. Now that the problem has occured again I am not able to contact adobe via email or hotline. Furthermore I cannot open the chat to contact adobe. Does anyone know how to solve the problem or how to contact adobe and ask them for help?
I contacted Adobe via 'livechat' to reset my account, then they recommended me to ask for support in this forum. Then they all of a sudden noticed that there was no forum about Adobe digital Edition (...which they should have been aware of before...), they offered to transfer my problem to a higher level and told me that an Adobe Assistant would contact me via email within the next 24 hours... I'll wait and see!
I have the problem that the 'livechat' seems to be inactive here in Germany (at least it is not possible to click the chat button). Unfortunatly, it is only possible to use the chat for the UK and it is quite hard to deal with a technical problem in a foreign language. Moreover, it is not guarenteed that adobe will actually reset the account.
However, there is a service hotline in the contact data of adobe. Sadly, the hotline does not support the 'digital editions'. I'll try to call them anyways tomorrow and look how far i'll get.
In my case the problem occured after the last update (to version 4). There are definitly only 4 devices authorized on my account. It is no problem at all when trying to open a e-book I bought. But when i want to read a book i borrowed from our local libary (via their internet service of course) adobe asks me to authorize the device again.
It seems that every borrowed libary e-book needs its own license.