Understand that not all real estate agents are Realtors. If you were dealing with a non-Realtor, then those don't apply.
And, yes, there are licensing boards. Here's the link for Ohio: http://com.ohio.gov/real/
As for collecting money owed, I agree with Ron's suggestion: Small Claims Court.
Hope that helps.
Or you can contact an attorney to discuss your options with regard to lost rents.