How to change/replace the device connected with an adobe account?

Hello.

I use adobe digital editions to place ebooks on my ereader. Since my laptop broke down I wanted to use digital editions on another computer. Hoever, when I register my account it gives an error message that I can only register with an adobe-ID which isn't used for the autorisation of a device. I contacted the chatbox to ask them to get rid of the old device connected with the adobe-ID but both the automated bot as the following-up guy couldn't help me. The following-up guy said I should post my problem in this community. That's the reason of this post. 

A somehow maybe related question on the troubleshooting & help page said that a problem can occur when there are to many device registered to my adobe account and that the limit is six (although I have only one registration as far as I know). However, it also says that I should 'contact us' to have the activation count reset. When I click the 'contact us' button the chat with the following-up guy appears back on who says he cannot help me. 

Is there someone who can help me here?

Rob