I had this exact issue and Sprint could not help. You have 2 choices.
1. If you have synced before the issue, you can choose restore from iTunes when you plug your phone to your PC or MAC and that will reset everything for you. Once you do this, turn off Voice Command though Siri can still be on which is OK. Then turn off Siri from the Home button to prevent this as well as better secure access to your phone.
2. Patiently tap each field of the password once, then 2ce; tap the first number of your password sequence once, then twice to fill each field until you enter all 4 characters of your password. The Home screen will unlock. Then go to settings and follow instructions in step 1 above.
What happens is Voice over requires using disability features so you have to swipe the screen using 3 fingers to move the screen and double-tapping each option in order to use it.
Voila, you have your phone back. I was able to resolve mine with these steps with help from my teenage son. Very painful experience!