Should cold-caller telesales people leave messages?

Hi guys,

For those of you who have used telesales freelancers from places like Upwork, Freelancer, etc., did you get them to leave messages when they hit the gatekeeper and so on, or do you just have them move on and keep dialing even though that's a lot of wasted calls? When you're cold calling, you can get a lot of that from gatekeepers: "So-and-so is not in. Would you like to leave a message?" If I'm hiring a home-based telesales freelancer for just one or two hours a day, I'm not sure what's the best way to go about that when if they leave a message, the person might call back hours later on the freelancer's own time. You're paying them for one or two hours per day but then they get a call-back three hours later on their own phone or softphone; it seems strange. Do you get freelancers to take those calls and then pay them in some way for those calls that come in (though I don't know how you'd track that)? Do you just get them to not leave messages and accept that those are dry, wasted dials? It seems a bit of a tangled situation and was just interested in some thoughts on that.