What block calls app do you recommend?
Late, but maybe this information is useful for you,
If you have your phone rooted I recommend the best: ROOT CALL BLOCKER PRO, this is a paid version.
If your phone is not rooted I recommend BLOCKER (embware), it is free and is very similar to call blocker pro.
You will find both in Google play store.
I have tried both and for me are the best.