Voicemail password not working

[jFlash]

Greetings,

I dialed in from a PSTN phone and setup the voicemail including changing the default password. I entered it carefully twice, as prompted. however, whenever I try to go to voice mail either through a PSTN gateway or directly by dialing 500, I get invalid login

My questions are:
1) if I forget my password, how can I retrieve it , reset it etc.
2) do other people have a similar problem.

Thank you for your help.