I changed from an iPhone to a droid and I don't know how to set up my voicemail. I've tried to *86 but it asks me for my mailbox number. I have tried the phone number, my password, and nothing. Helpvoi
You probably should call customer service from another phone and ask them to reset your voicemail feature to the style of voicemail you want either the Basic Voicemail (Free) or the Basic Visual Voicemail (Free) if your phone supports it or the Premium Visual Voicemail ($2.99 per month).
If you had any saved messages in iPhone voicemail system (Apple servers) they are likely lost.