I have yet to see a blocked number make it through our blacklist. Even if you somehow make it through, our receptionist is quick to send you to black hole of an inbox that NO ONE ever checks and is purged daily. Good luck getting through our black list or the inbox no one ever answers.
Call claims to be from AT&T's fiber internet expansion team, clearly this number is spoofed and some bs telemarketer in the Philippines and sometimes India. Gave myself a pat on the back for never having to hear from this specific number; doesn't mean this company has this only number. They probably have hundreds if not thousands of other numbers they can spoof their calls with.
I just received a call from this same number that claimed to be from AT&T's fiber internet expansion team. Some Philippine asking me when my contract with AT&T expired and what am I paying. He could get me higher speeds for the same price. I told him that if he worked for AT&T, he would have all of that information. He then told me he was a 3rd party supplier. I told him that he misrepresented himself and asked him what company he was from. He said he couldn't tell me and hung up.