I have entered the numbers to be blocked, but why the calls from those blocked numbers still coming through and ring on my phone? Does the call block actually work? When I tried to enter and block the number again, it shows that the number is already in the blocked list, but still not blocking. Why?
Your may be a victim of caller id spoofing. See article:
Apparently, spoofed numbers can slip through caller blocks. However, I have used a call blocker device, a piece of hardware sold commercially, that can control phonecalls you received in different ways. One of the ways is to only allow numbers you program into the blocker to come through. Its called the whtelist method vs the blacklist method. This may or may not work for you depending on your situation.