How to return both my activations as one

Please

I need your assistance with Adobe Digital Editions program.

Initially the program was installed on my computer and E-reader This arrangement was working fine until recent times, I purchased a book from "booktopia.com.au" which would not download to the computer or E-reader.

When I contacted them they suggested I de-actvate my Adobe Digital Editions and then reactivate which I did, it now allows me to access a "Epub" file which I can read on my computer but not the E-reader.

With the re-actvation I cannot read any of the Many previous books I downloaded onto the computer, but I can read on the E-reader. Can you assist with returning both my activations as one, onto my computer so that the books can be accessed by the computer and E Reader.

Yours Hopefuly