Sprint HTC Hero :: Block Private Calls?

i have tried nearly ever single application on the market that claims to block private numbers but it none of them work for me... Idk if its because of the Sprint service or the applications just dont work. I know GBlocker blocks the calls. But it dont block the texts, or prevent it from going to voicemail. Nor does it block private calls. There was this other one I had that blocked calls too but same thing with GBlocker. What i dont understand is that if you choose the option "BLOCK ALL CALLS" it will then block private calls. But the option to just block the private calls fails to work. Is there anything out there that actually works? I have considered buying extreme blocker for $5 but whats the point if it might not work? When blocked numbers call, i dont want their voicemails. Nor do I wanna know their calling.