Listen to the mobile box without credit?

Apparently you should be able to listen to your mobile box without credit on your laptop. You have to sort of three. At but I don't understand it, it doesn't work for me. But it would be really important that I listen to these messages!

So for me I can listen to my mailbox on my mobile phone without credit and on a laptop that would be impossible because the SIM card is not inside.

How does it work without credit?

Well call your mailbox 🤷♂️

That will not do.

Then don't stop with me. Then load up

At three. At you can have the voicebox messages forwarded to your email address. Here is some information:

https://www.drei.at/de/privat/produkte-und-services/drei-box/

If I could I wouldn't try it for free