Were you in touch with them before designing it around them? I would think you should confirm they're available for that volume of work before designing the project around their style or their prices--and plus, sometimes prices change based on who the client is and what usages they're going to need. I do think you guys jumped the gun a little if you hadn't talked to them at all before moving ahead. If you HAD already talked to them about this, it is rather unprofessional of them to not respond anymore.
But regardless of that, at this point I would try to private message them on the platforms you know of (instagram, twitter, or facebook page), and if they're local, maybe you know someone that knows them personally who could contact them for you?
I think it's cool you're trying to hire a local artist though, and it would be awesome if you guys looked for another artist in the community before turning to online or an agency. It sounds like a great opportunity for someone.