why pick up the phone if you could just put down a placeholder banner saying something like "do you want your company name here? write [an-email-address-thats-not-your-personal-mail]".
If the project is really becoming a local hit then you're bound to get contacted.
Alternativly or additionally you can ask for donations on that banner. And a link where OP explains his situation, no profit, just costs, but like to keep the thing running.
If the project is really becoming a local hit then you're bound to get contacted.