keeps calling and leaving blank voicemails. super annoying.

Oxford authorization department

Legit!  This was a recorded call on behalf of United Healthcare letting us know that my daughter's MRI studies were now approved and she could schedule the test.  South Jersey Radiology required this authorization before allowing us to schedule; so in our case, this was good news.  Caller ID displayed "Evicore."  Not sure how to categorize this; so I will pick SMS.  Hope this helps!

Asking for personal details, without mentioning who the call is from.

It had said that the requested service has been approved and the authorization expires in May. Without explaining what type of "service" it is which I had not called for to anyone.