sounds like Lenny which is an anti telemarketer SIP bot you can forward calls to:

https://www.youtube.com/watch?v=p5IKbFATKLo

I usually just say "please hang on, while I get my credit card", and then just leave the phone off the hook...

This is amazing. I wonder if anyone has done something similar for email spam.

if you're interested in more of these calls (some are quite funny) there's an entire reddit dedicated to it:

http://www.reddit.com/r/itslenny/

I think that's a person playing back pre recorded sounds. AI isn't advanced enough to impersonate a telemarketer.

It is. Offshore telemarketing - no more fake localized names and accents, just hire a person who understands spoken english and install the MidwestFemale 3.68 module.

I had no idea they were using this type of tech already, the second call is so smooth.