John is on the right path. I'd only add a different perspective.
It is very tempting to offer incentives, especially when no one talks to you. I have been there.
The problem is that you'll end up with paid research (I learned from this mistake, as well), not knowledge about your prospective clients.
When you talk to prospective clients, there should be a continuum connecting learning about their pains, proposing a solution, checking their true intention to pay, to (hopefully) they begging you to take their money.
It is the theory, and therefore, easier say than done.
Still, you can offer to pay for their coffee, lunch or dinner, if you want to entice them to talk to you, again.
Best of luck!