You can always do things via mail, phone, or bicycling down to the local Gemeente office. I just don't know what the authorisation methods are for mail/phone be

You can always do things via mail, phone, or bicycling down to the local Gemeente office. I just don't know what the authorisation methods are for mail/phone because I use the DigiD methods. You can make the digital side of things secure while still having accessible method for non-technical people.