1.) You can now understand what it is like from the decision making perspective.
Listen to what they are saying. Did they lose you right off the bat? Why? Did they grab your attention? Why?
Throw an objection at them- maybe one similar to those you hear the most. How did they respond?
And my favorite exercise, assuming I see some potential-
2.) Sell the telemarketer on your services. They talk to a lot of people day in and day out. They are motivated by money and by sales. Lead the conversation to how they can actually make more money off of you by sending you referrals. Or maybe they actually have something that can help you!
Or don't, because there is always someone who "has enough business" and is not interested in evolving.