Here's some great advice on leaving messages for prospects when you are cold calling from the Marketing Mix Blog:
"Very often, when you are reaching out to prospects who've never heard of you before and you make an initial round of phone calls, it's essential that you leave a message. Frankly, if you don't, it's a waste of time. You may think it's not worth leaving a message, but that only makes sense if you think that leaving a message is about getting a call back. Don't expect that. People rarely call back these days, which is fine."
Read more here.
MLM Marketing Blog