Can you try dialing your own number from another phone and press # symbol when you hear the greeting to interrupt it? Then see if you can input the password correctly.
I'm most definitely NOT a VZW employee. If a post answered your question, please mark it as the answer.
You don't press the # sign on your cell phone when you do this.
Don't answer your cellphone and let it go to voicemail. When voicemail picks up, THEN press # on the phone you are calling from to go into your voicemail menu. THEN try entering your voicemail password.
If this does not work, you can reset your password from your MyVerizon account. You can probably also do so by calling CS @ *611.