how i authorise my new computer with an old VENDOR ID keeping in mind that this VENDOR (COSMOTE BOOKS) does not exist any more and the ADOBE ID system does'nt offer me an option to authorised my computer aiming to have access to may older epub books

I used an VENDOR-ID and get e-books some years ago. Now this VENDOR (COSMOTE BOOKS) stopped his operation. I try now to authorise a new computer with this VENDOR ID because I want to have access to my old books "connected" with this VENDOR-ID. THE AUTHORISATION SYSTEM OF ADOBE DIGITAL EDITIONS doesn't offer me a way to do so. (In other words I LOST my books?) --- SO,  HOW I CAN AUTHORISE MY COMPUTER with this dead VENDOR ??? I hope that ADOBE has a solution.  Any proposal ?