If you want to move your current/previous voicemail messages from your carrier over to YouMail, you can but with a little work. This is our Drop Box feature.
First you'll want to get a hold of the messages as audio files; Either mp3 or wav formats are fine. Next, you're going to email those audio files as attachments to your YouMail Drop Box email which is firstname.lastname@example.org. The 10 digits before the "@" is your phone number. Once that email is sent, the files will be deposited into your inbox just as any new voicemail message would. All alerts and notifications would then apply.