Also had the 3€ invoicing fee charged for July's invoice, even though I had e-invoice enabled already for June's invoice, and nothing charged then. Should be noted that this is a separate item from the monthly fee, which makes it even easier to miss (as after seeing the monthly fee, I would at least stop keeping an eye out for other charges). They pushed back initially, but told that they would refund the fee as I messaged them saying that I had e-invoice already active in June.
Unrelated rant; the way Aktia tracks and dates the transactions is incredibly poor and makes it incredibly hard to track one's spending, as dates and amounts (if foreign currency used) change around constantly. I could see this weird time stamping of transactions cause problems when trying to determine if the criteria for the 3mo welcome offer was met, but luckily spending more than the needed amount anyways so shouldn't be an issue.