Your voicemail messages will be send to you by e-mail in an audiofile. Open the e-mail with the audiofile on a different computer or smartphone to make sure it’s not a local problem. It might be the format of the message (WAV) that isn’t recognized by your device. In this case, you should download the adequat program to be able to open this kind of files.
If this does not work, contact us at firstname.lastname@example.org