Ok guys, I couldn't get my Voicemail on Rogers to work. Then I called and got the backdoor number. I'm in Toronto so it's: +1-416-357-3229.
So all I did was key in: *5005*86*+14163573229# and dialed. Now it works!
To dial the "+" just tap and hold "0"
I hope it works for you like it did for me!