Annual service-cost settlements can land as a surprise bill for several hundred euros, many months after the year they cover. Tenants who assume the figure is simply what was used often miss two things: the deadline the landlord was obliged to meet, and the underlying invoices they are entitled to inspect.
Service-cost settlements running into the hundreds of euros happen more than they should, and no, you're not stuck paying just because a bill arrived. Your landlord is legally required to send an itemized annual statement within six months of the calendar year ending; miss that window and they lose the right to bill you extra (though they still owe you any credit balance, deadline or not). Ask to see the underlying invoices, not just a total figure — you're entitled to that, and it's often where the padding shows up. If the numbers don't add up, or the statement arrived late, you can take it to the Huurcommissie: the tenant fee is a modest €25 (refunded if you win), and you generally have up to 24 months after that six-month deadline passed to file.