The "one euro" transaction would be a credit card confirmation that they run when you register a card, separate to the subscription.

Beyond that, I'm not sure, but did you start on a preferred server with the "Road to 70" EXP boost? If so then I think you get 15 free days of subscription when you reach Lv30, so it's possible that you're now receiving that 15 days and your next paid renewal will come at the end of it.

I don't think it normally says how many days are remaining. If you signed up with your credit card then it will automatically renew at the end of the month, so maybe it only shows the countdown if you paid for a fixed amount of time (eg. with a time card) and it's going to expire without renewing.