Well that was unfruitful... I've just talked to a game advisor in live chat and he couldn't help me because I couldn't remember the answer to my secret question.
He gave me a case number and directed me to the "specialized team" which basicly means i'll have to call anyway. So people just expect I can afford to ask my boss for a day off so I can get my origin account back?
It seems giving a correct origin ID + e-mail address + gamekey + first and last name isn't enough to verify the account is actually mine...