The number you see does not tell you who is calling

The number on your screen was filled in by the side that called you, and nothing on the route checks it. That changes how you establish who you are talking to.

The number on your screen was filled in by the side that called you, and nothing on the route checks it. That changes how you establish who you are talking to, and it decides what you can still find out afterwards.

What caller ID actually is

The number your phone shows is a field the calling side supplies. There is no check along the way that establishes the caller is entitled to the number it presents. What countries do about it blocks certain traffic on its route, which is not the same as verifying the number, and the last section says what that covers.

There are ordinary reasons for that field to be fillable. A company with a hundred extensions presents one main number, and a service calling on behalf of a client presents the client's number. That is why the field cannot simply be sealed, and it is the same mechanism fraud uses.

Two situations that look alike and are not

Both leave you not knowing who called, and they lead to completely different routes.

For a withheld number the law is on your side. Article 11.11 of the Dutch Telecommunications Act gives a subscriber troubled by nuisance or malicious calls the right to ask their own provider for the caller's number, name and address. In Belgium the equivalent is the Ombudsdienst voor Telecommunicatie, which identifies the suspected caller on request, and the request comes from the person who was called.

A faked number falls outside that. The number was not withheld, it was replaced, so the statutory identification route does not apply. What remains is a police report, because only an investigating officer can require traffic data from a provider.

Do not let a number identify a person

Caller ID is not proof of identity. An incoming call that matches a customer record tells you which number was presented, not who is holding the phone. Anyone who can read your website can present the number on it.

So do the identifying with something else: a detail the caller has to know, a code you put in the ticket or the portal, or a call back on a number from your own records rather than the one that appeared. If you do not trust a call, end it and call back on a number you look up yourself.

Returning the call on the number you saw reaches its real owner, who may know nothing about any of it. If people are calling you back about calls you never made, your own number is the one being misused: see Your phone number is being used for spoofing.

Where to report it

If you do file a report, we will supply what we hold about the call: the date, the time, the duration and the number that was shown.

What is being stopped and what is not

Since 2024, Belgian operators have had to block calls that arrive from abroad, show a Belgian number and are heading for a Belgian number. Outside that duty fall faked text messages, calls that originate inside the country, calls that arrive showing a foreign number, and calls you receive while you are abroad yourself.

The Netherlands has no such duty. Spoofing is prohibited there, but blocking has not been imposed on operators.

Assume in both countries that a faked number can reach you. That is why the identifying has to happen in the conversation and not on the display.