Voice Mail Goes to busy Signal?

[osso12]

I have had my Iphone 4 since christmas and am just now realize there is a problem with my voice mail. I always have my phone on, So I did not realize there was an issue with it. When I got my phone I set all my VM options up including a greeting. Someone told me they tried to call me yesterday and it goes to a busy signal if I don't pick up the phone. Sure enough, I called from another line and it goes straight to a busy signal. What is happening here as I want my VM messages?

 

[osso12]

resolved via at&t

 

[pigeon]

i'm gonna have to try it on my own too...i haven't gotten voicemails in forever...
just to help everyone else out, how was everything resolved via at&t? can we get a little mini summary?