Prison Ministry Visiting Booking Software/App

I work for a prison ministry. We help people visit their loved ones in jail. I need a program and app that we can use to ensure we are not overbooking the buses and not sending extra people to visit the same inmate on the same day, as there is a limit. The software will be used in a call center environment for a nonprofit. There will be no transactions on the software itself. We will be taking credit cards over the phone. We need something to input information in, the day, time, and passenger amount in the software as well as the name of the inmate the person is visiting. The software needs to be able to tell the call center agent how many seats are avalilable on the bus and if that inmate has any visitors scheduled on that day.