Snap upgraded their voicemail system a while back , in August I think. 

I had noticed in the back of my mind that I hadn't been receiving voicemails by email in the usual way but didn't really have time to look into it until I noticed a bunch of new voicemails piled up today. 

Figured out, you have to go to the snap account and add your emails to the voicemail list to re-enable voicemail emailing.