Adobe Digital Editions can't open acsm

Dear community,

Since Adobe has thought it funny and prudent to hide their contact information deep enough on their website that one might suspect assholish behaviour, I humbly request youtr help.
A while ago I bought a book, which apparently has the acsm format (sth I deeply regret and will vow to never do again). I tried opening it with ADE but I get the error code "E_LIC_ALREADY_FULFILLED_BY_ANOTHER_USER". As far as I understand, this error could be appearing because I previously tried to open it without registering my adobe account when using ADE, so the book is already "in use" by someone else (namely logged off little me).
How can I reverse this ******** error?

Best regards
Another user fed up with bs DRM