Can medical appointment information be told if you are on record as caregiver?

Mother has Kaiser and tried to find out appointment information over phone and they would not release information with me. I'm on record with Kaiser as a caregiver and there is a release on file that I can make or cancel appointments. Mother stated that someone had called but could not remember when or who and cancelled the appointment. She could not say why they cancelled or if a new appointment was set up. She is in assisted living and with COVID there is a lot of issues taking her out and setting up taking her out.