Too much ADE authorisations

Hello community,

I have Digital Editions on my laptop + on my Pocketbook Inkpad Color 3 e-reader. Now I want to authorize my second e-reader (a little one 'for the road') ... but ... I appear to have too many subscriptions. Thinking of it: yes, I did something wrong: I did a factory reset on old items to sell them, but I forgot to deauthorize them first. Is it possible to delete all superflue items from our account or not? I really need the authorisations to be able to keep reading my drm books. 

(sorry if I made mistakes, English is not my native language)