Wiki Medicare New VS Established PT

I work for a group of Radiologist and we have a patient we have never seen before that came to our interventional clinic. We billed the patient out as an new patient (99203). (please note we have never even billed out an imaging for this patient) We received a denial on this as the patient was seen by a different interventional radiology clinic in October 2022. Even after appealing and calling Medicare they are stating that because its the same specialty (even thought its a completely different entity) ours is considered established.

I guess I am confused. Is this how it is? Am I missing or misunderstanding it?

Did your current radiologist work for that different radiologist back in 2022?

He did not. I am going to do a second level appeal!