I've been getting a lot of spam calls from the 212 area called lately.  When I picked up, I got the customary silence of telemarketing calls.  When I called the number back, I got a very homemade sounding "this number is not in service" message.  Very suspicious. Blocked.

It's from a "lower your Con Ed bill" scam operation.  The number really is not in service - it's faked Caller ID that shows up.

Same here, hangs up

I got the same call and like all tele market calls I ask them nicely not to call back. If they do call back I get rude on the phone. I do not yell at them or anything like that. I ask them to hold on for a second and they I go into the bathroom and start making a lot of digesting noises and grunts. I complain about eating spicy foods and such. After about a minute I get back on the phone and apologize and if they are still on the phone. I ask them if they ever had a tough movement like the one I just had. I drive the phone conversation into the subject of bathroom rituals.

these a$$holes call me every day.  it doesn't matter if i request to be removed from their list or not.  so i now generally press 5 to talk to someone and answere there questions until i get another call or get borded.  i figure if i can waste their time then i can save someone else from being bothered by them.  yes, they say that they can lower your electric bill and deceptively try to tell you that they are actually con edition (the local electric company in new york) but they are not.  they talk about 'recent deregulations' but it has probably been a decade since these deregulations went into effect.  a total scam.  i like to answer all of their questions (with false information), make them think they have a fish on the line... and then at the very end tell them that i will think about it and ask how i can call them back.  they usually hang up at that point.