My neighbour below me rebult their appartment, and made bigger kitchen by using the space of their balcony.
This is not allowed without the explicit prior approval of the association/the meeting.
There is damage on my balcony floor, and the water is leaking to their kitchen below.
If by balcony floor you mean the finishing layer it might be yours or the association’s, if it is the balcony construction it more than likely is communal property that belongs to the association.
If the damage is the result of the (illegal) reconstruction of your neighbour’s appartment he is liable for the damage. If it is communal property that was damaged the association has to address your neighbour, and the association should carry out the repairs required. If yor neighbour damaged your (non communal) property you yourself should adress your neighbour and you should take care of the repairs.
They say it is not part of VVE and I have to fix my balcony floor with my own money.
To be able to check whose property was damaged you will have to read the deed of property division. Therefore you have to get the deed from the Netherland’s “Kadaster”.
First thing to do is get the date of the deed of division, and you should also check if there is a socalled framework regulation given in the deed. You want to find this out first.
Next post gives the link to the internet page of the Kadaster (not in English) where you can get the deed (will cost you €16,95).