I just got a call which I will add to my block list. I will now get no ring but will get a list of blocked calls on my phone.
I have the Panasonic cordless telephone Model kx-tg6842b (2 handsets)
You can block 250 numbers plus kill the one ring that existed on earlier models that only allowed 30 blocked numbers.
The one handset model sells for $70 at Amazon.
I had never heard of Operation Smile.