I use the Jolly Roger Phone Company to answer my telemarketing calls. Here's why:
The Jolly Roger Telephone Company provides automated "bots" to chat with your telemarketers. These are designed to keep unsolicited telemarketers engaged for as long as possible. The bot will engage the telemarketer and keep them busy.
The goal is (1) to waste telemarketer time and (2) for telemarketers to eventually learn that your phone is protected by Jolly Roger and to stop calling you. Oh, and there's (3) entertainment as you hear these telemarketers try to scam the bots.