Too many activations

I've had troubles with a Kobo Clara HD and received a new one but now I cannot authorise with Adobe Digital Editions.

E_ACT_TOO_MANY_ACTIVATIONS

From the program, I've tried to contact support but after three "specialists" I get the recommendation to try this page.

Why not put something on the FAQ for this?

Anyway, can someone help me to resolve this issue?

Kind regard, 

Peter