I am also having an issue authorizing my device re: my sony PRS-505; I have had my ereader for over 2 years and only recently have I had an issue. Phone and Web support is lacking. Contacted both Sony and Adobe on Saturday and again on Monday.... Could someone fix my problem.
Support for Adobe Digital Editions through Adobe is only available by submitting a web case (go to http://www.adobe.com/support/digitaleditions and click on "Submit a web case"). Have you done this and if so what was your case #
Sony however does offer phone support and should also be able to fix your problem.
My case number is #203321980
You went through the chat support (who incorrectly sent you to Phone support). The only realy method to get support for Digital Editions is by submitting a Web case (given the steps detailed above).
I did however fix your immediate problem (you have 4 device activations left).