It's Beta so it's normal that not all features are fully or properly working. pretty sure they will fix it in final version and meanwhile you can go back to previous OS or stay with current one and report the issue to the developer
Dial your number from the dialer and login using the PIN that you set when you first created your voicemail profile. Some if not most Galaxy devices have it setup so you can press and hold 1 in the dialer and call voicemail instantly.
Is it the one Verizon typically uses that is red? If so, you may end up having to wait until Verizon updates it. Other carriers have their own version of visual voicemail but whether it would work for your device is questionable.