Jim Browning got a look into a Kolkata call center via one of the scammers' insecure machines: "You're looking at the webcam of a scammer named Deva ██████. He's currently uploading the phone numbers of people who will be his next potential victims. All are numbers of people who have previously fallen victim to a popup scam."
These guys are a particularly nasty group from Kolkata in India. They run a refund scam and this video shows what their call center looks like, how they operate, who and where they are. I've sent a link to the unblurred version of this video to the Kolkata Cyber Police (for all the good that it will do).
The offices are "small and cramped" and full of smoke.