This article should help you find out your voicemail access number:
What do you mean it doesn't show your voicemail number? It's right there, where it says “voice call forwarding when unanswered forwards to: +16475804001”.
Timo, it isn’t showing the number the instructions say. It’s supposed to look like 5555804001*11*10. It confused me. I don’t process new information easily.
It would be helpful is the showed a screenshot, or said the number is found in the first entry on the page — for some of us who need things explained in detail.