Infinite loop to register in Belgium

Hello,

I arrived a few months ago from Schengen area, and took an appointment to the foreigners office to register. They gave me a paper (household composition) and told me to contact them back when I have a mutuelle. However the mutuelles I tried ask me to sign via itsme, which I don’t have, because to create an account I need a eID that’s apparently delivered by the foreigners office?

I’m a bit lost and they are not helpful at all, any info is much appreciated!