As others have stated - DO NOT EVER answer unknown calls and NEVER call the number back. Asking a criminal telemarketer to "put you on their do not call" list is an absurd notion; these criminals are already breaking the law by calling you - it won't happen! Do not have ANY interaction with telemarketers and DO NOT "press 1 to be removed" from their call list. By calling the number back or pressing 1 (or any other number,) you confirm to the telemarketer that you have a "live" working phone number - a number that can be sold to other telemarketers! You have voice mail and/or an answer machine - use it! Legitimate businesses/callers will will always leave a message. The Do Not Call List was designed for legitimate businesses to check BEFORE calling you. The irony is that now days, legitimate businesses generally never call their customers. If you receive repeated calls from telemarketers, you can report the number(s) to the Fed Gov Do Not Call List. They will investigate the calling number but 99.999% of the telemarketers use spoofed numbers. Spoofed numbers cannot be traced and criminal telemarketers change numbers often. Purchase a call blocking device (for land lines,) if you can. There are a number of blocking apps for cell phones. Most modern cell phones have blockers already built in. You can report the telemarketer calls to 800NOTES.com. This is a free service that allows victims of TM calls to report their experience. I report all TM calls to 800NOTES.

I just don’t answer the phone. About 95% of the time.

I buy everything they offer, hang on every word and ask if there is anyway I can send even more money.

I’ve been on the Do Not Call list forever but have recently seen an uptick in robocalls. I sincerely think telemarketers don’t care anymore as they know the current administration won’t likely prosecute. Sigh.

I recently had one shout at me on the phone because I didn't let him finish his script. I usually just say no thank you and hang up

I simply put the phone down and let them keep talking until they finally realize there's nobody listening. Waste their time.

I deal with them with much less patience than I used to. If I don't know the caller, I typically don't answer the phone, but every once in a while, the number will look "legit," and I'll answer. The last time this happened and it was a telemarketer I was rude, probably for the first time ever. I just said, "I don't want to talk to you right now." LOL! Immediate hang-up on the other end.

My land line has been handled by the answering machine. You would think by now they would give up, right? Boy they are persistent. They keep calling all the same, they just don't even bother to say a word to leave a message. They know but they let it ring to trigger the answering machine anyway. At least I don't have to deal with them at all and it's easy and quick to clean empty messages.

I mess with them if I'm in the mood to or I tell them it's a recorded line and start asking them questions, usually they'll put me on a do not call list themselves because of it.

Put a bot killer on your phone

If you are not in my contacts I don’t answer. I am so bored with them.

I try to be nice to telemarketers. Most of them are just low wage workers who are just trying to earn a living. If I can get my claws in to one of their bosses though? That's a whole different can o' whoop ass.

Download a block app like black list. When they call just answer and set the phone down. Sign up for the [donotcall.gov]. Tell them they have the wrong number. Call their bluff and tell them you know they are calling from Africa. Can do like I do and ask them as many stupid questions as they can handle, they will eventually call you a name and hang up. You can try the heavy breathing technique. Tell them that you charge 1500$ a minute to waste your time. I had heard a news report that said if you tell them that you get 1500$ a minute to listen to their spiel they can be billed for that.

I usually hang up.

In the unfortunate event that a telemarketer gets through to me I will engage them in meaningless, trivial conversation. I try to keep them on the line as long as I can. I figure I am helping out some other poor fool from getting an unwanted phone call. I do it for all of you. You are welcome.
...unless I am in a foul mood.