[2] Once you click that embedded voicemail hyperlink...
Rule number one to be safe online: NEVER CLICK ON LINKS IN EMAILS, especially if you don't know the sender (whitelisting).
This is relatively easy to be safe online. We just need to develop the right skills and behave carefully online. Do not trust anyone, download anything from unknown sources, and always check the electronic signature with PGP when, for example, when we update the Bitcoin wallet to the last version from the source page.
One more time, remember to: NEVER USE ANY LINKS PROVIDED IN EMAILS.
If there is no other way and you have to use a link provided by an unknown third party, you should always properly check it for viruses (VirusTotal, etc.) and open it in a safe environment, like a sandbox or virtual machine. This is the only way to avoid infection.