Airline (lowcost) has changed my reservation, what are my options?

An airline in question has 3 flight a day to my destination, one ridiculously early in the morning, one in the afternoon, and one late night. Because the afternoon one was the only one convenient for me (travelling with baby), I've booked afternoon one, even though it costed a bit more. A week later after I've received following email:

Unfortunately, we had to change your booking. We apologise for any inconvenience this may cause you.

Please carefully review your new flight information (date, time, flight number, airport of departure). If you agree to accept the change, please click the button in the lower left corner of the page. If you do not agree, we advise you to contact the call centre to change your booking (in that case a surcharge will apply, as listed in the fare conditions and general conditions of carriage).

Please be reminded: it is essential that you respond to this e-mail, since we need to know whether you are aware of the changes in your booking.

The change in question is changing my reservation from afternoon to late night. Thus far I did not accept the change nor acknowledge that I'm aware of it.

What are practical options to deal with the situation?

Airline is based in the Netherlands, thus EU and Dutch regulations apply.

As for fare conditions, seems that relevant part reads:

2.The applicable flight schedule is the flight schedule that applies on the date of departure. The flight schedule may be amended after the Ticket has been issued. In that case, the Passengers will be informed using the contact details provided when the booking was made. The Passenger is responsible for providing Carrier with his/her contact details through which he/she may be contacted in the event of changes to the flight schedule(s). Nevertheless, Passengers must check with Carrier prior to the scheduled date of departure whether the flight schedules as stated on their Tickets have not been changed. In the event of a change to the schedule that is inconvenient to the Passenger, the Passenger may request a refund as referred to in Article X(2)

However, not sure how can I verify, that they actually canceled the flight, not just overbooked (it's 6 months from now, so it doesn't show up on airport's timetable yet).