Track Attendance of dial in only participants> We proved a call in number and an Audio only attend

We provided a call in number and an Audio only attendee number to log in in mute only mode. this is for attendees that do not have a smart phone or other devices.  However, we know they are there but there is no way to track them or even see what phone number dialed in. I need to be able to track who just calls in by at least a phone number.