this number called my phone multiple times with, no message,no answer

This is a doctor office

received a call from this number called it back its not in service

This number is from the Princeton Hospital...I got a phone call from this number and when I tried to call it back it said that it was disconnected.  I have a relative that works at the hospital and occasionally calls me from there and I wondered if it was them.  I got a hold of them just now and they said that yes it was them and that they had called earlier today from that number.  I am sure that it says it is disconnected because it isn't their main number and they don't want personal calls being made directly.