When you reach an employee, not the customer, professionally request to speak with the individual.
By definition, this person handles all inbound calls to that company. He or she answers for the company, then transfers calls. Company receptionists sometimes take messages; however, most often they move you into voice mail. Depending on the size of the organization or level of responsibility, this person may have a tremendous amount of information or may have nothing but an extension.
You need to find out what this person knows. How? Start a brief conversation with her, building rapport as you go. For example, provide partial disclosure to her.
Receptionist: ACE Construction, this is Linda, ...