Tutorial for perfect Voicemail call forward settings

[Deliverance]

This might be an issue because I signed up for Freephoneline so long ago (it also never asked if I wanted credits to apply to my "Mobile" or "Desktop" account).

Anyway what I desire!

I use Freephoneline to forward to my cell phone. Which is with Mobilicity, they charge $8 a month for voicemail. Since Freephoneline has call forwarding and voicemail (but limited SMS and MMS) this is a perfect match!

If someone has a tutorial on how this can be set up so that no one receives a User is Unavailable message that would be HUGELY appreciated.

This feature should definitely be at the top of Fongo/Freephoneline's priorities as many calls are lost and with this feature enabled Freephoneline is severely degraded in terms of reliability.

Any help would be hugely appreciated!