Make sure the Voicemail Password that you enter is correct. If you don’t know your Voicemail passcode, here are couple of ways you can reset the Voicemail Password.
Tell customer to log on to My Sprint. Click My preferences tab. In the Things I can manage online section, click Change voicemail passcode. Click Reset radio button. Click Save. Tell customer the passcode is the last 7-digits of the phone number.
From Self-Service Reset *2
Dial *2. Press Send, OK or Talk key. Press 1 to confirm or enter the phone number. Press 4 to ask for help with account. Press 2 make a change to your account. Press 3 reset voicemail passcode. Press 1 Yes to confirm passcode. Tell customer the passcode is the last 7-digits of the phone number.
Voicemail Access from Landline
Hope this helps