If it’s urgent, they will should leave a message (instead they keep calling and complain that “it’s hard to get hold of me”).

This fucking kills me. The people who I screen the call, they go to voicemail, they hang up and try again, I send them to voicemail… it’s infuriating. Voicemail exists for a reason! And yes, my experience mirrors yours in that the same people will say they have “no way” to reach me.