Hi.  I found that I had to clear all the deleted voicemails from the phone in order to get this to go away.  It's a nuisance.  Also, I found that even though I cleared the messages off the physical phone, there were still voicemails on the carriers voicemail system that needed to be cleared.  So, I called my own number, used a password I forgot I setup, and manually cleared 20+ messages on that system as well.  Good luck.