OK, bare with me.
On my Note 4, I can send numbers to my voicemail, but not block them. I think your carrier may be able to do that.
I can, however, send them directly to voicemail without my phone ringing. It will tell me I have a voicemail afterward though.
I reject the calls by refusing to answer the call first, or hitting the red 'reject' indicator when my phone rings, then by tapping the number in the call log, then the three Setting dots, (top right?) and in the new menu, choosing anything that remotely says "Reject this number."
Completely blocking a number may require an app, or your carrier may need to do it, if it can even be done. In my 15 years of owning a cell phone in the United States, I have never uncovered a method of blocking a number completely.
I hope this helps.
12-27-2015 05:05 PM