Google voice doesn't require to use their number. You forward your phone to the number they gave you. Mine works fine.
When contact calls, I don't get a ring..if I do, it is so brief I never noticed it.
Just confirmed, no ring. Screen doesn't even light up. Straight to google voice mail.
Sent from my DROID RAZR using Android Central Forums
Have you tried Mr Number?
A couple of times after finishing a call I have noticed that it had blocked a call. Didn't interfere with the call I was on.