Messages left with staff

I call my senators weekly to let my voice be heard. Today I asked a staff member who answered how my message reaches my senator, ie: are they writing what I say down, is it recorded and then played later, do the voicemails I leave get listened to by the senator, etc. They repeatedly said “I’ll pass your message along” without advising how this happens, despite me asking 3 different times on the call. So, how does this actually work? Do members of congress actually receive/review messages from constituents? What happens to my voicemails or when I get a staffer who “takes my message”?