Indeed, all eggs are in one basket in Belgium. It is hard to find any exceptions whereby a government agency is independent and sovereign from Microsoft Corporation.

(edit) Can you fax them? Some agencies still have fax numbers. Not enough of them… it’s a shame to see fax die when it is the only somewhat universal electronic way to send a message without exposure to surveillance advertisers and their walled-garden barriers. This question really boils down to: are the fax numbers going to an inhouse decoder, or are they just 3rd party cloud services that repackage the faxes as an email?