I don't know what ATA you're using, but I was having a problem with accessing VM through *98 last week. I was getting a busy signal. This is how I fixed it:
Went into the Star Code profiles via the expert mode of ObiTalk and changed Code28, Blind Transfer, from *98 to *99.
I found out about this by reading a configuration guide in the Fongo community forums here: http://forum.fongo.com/viewforum.php?f= ... 76142e3f5d
I also updated my digitmap based on the PDF guide for the OBi200. Since I did both those things, I haven't had any issues with the service (it's been about 5 or 6 days now).
In the meantime, you can login to your freephoneline account via freephoneline.ca and change your Voice Mail to Email setting under "Voicemail Settings". If you choose "copy" you'll get the messages sent to your email and can also check them via the phone (when that's working). If you choose "forward" they'll only be sent to your email.