How to call a 6 digit 13 number from overseas?

Is it possible to call an Australian 6 digit 13 number from overseas? I always thought 13 numbers don't work from outside Australia, that's why Centrelink and the ATO have numbers to call from overseas.

I'm currently living in France and I need to call my insurer (Honey) to finalise a home insurance claim. Their only contact number is a 6 digit 13 number. They told me to add +61 but I still can't get it to connect. I've asked them if there is an alternative contact number I can call from overseas but there isn't.

They're adamant I have to call this number to leave a recorded voice message to finalise the claim.

Is there something I'm doing wrong? I can still call regular mobile and landline numbers in Australia so it's not my phone.