We are a library, and we need to extend the authorization limit because we need to have more then 5

I don't think you will get the answer on this forum.

You could try Live Chat.  I don't think they will have the answer either, but should be able to point you to the right people at Adobe.

Adobe Live Chat: http://www.adobe.com/support/chat/ivrchat.html,

or as a slight short cut try http://helpx.adobe.com/contact.html?product=digital-editions&topic=using-my-product-or-service

Choose topic ‘'Signing into my Account' , and then click on 'I still need help';

then you should see 'Chat with an Agent' at the bottom of the page.

Depending on screen resolution, you may need to scroll down a bit to see the Chat with an Agent' bit, just under 'Ask our Experts'.

'Ask our experts' will indeed just lead you back to this forum.

Sometimes you will get ‘Sorry! All agents are busy— please check back soon.’

Don’t refresh the page, just hang on and it should eventually go to ‘Chat Now, and agent is available’.