It would be a deal breaker for me. Confidentiality is a very important issue for me, and I would not be able to trust my T if I did not know for certain that everything I stay remains between us two. It's one of the few things I've asked my Ts about at the first session. My current T has no billing person, he handles all that himself (he bills the county, and only tells them the clients' name and personal identification number and the date of the visit), and my previous T also submitted only the name, ID number, and date to the billing department at the clinic she worked for.

I know for a fact that in my country it is against the law for a licenced T or psychologist to allow any other person access to their session notes; if a diagnosis is needed for insurance purposes, they write a statement but do not provide a copy of their notes. (There was an article in today's paper about a psychologist who had left a patient's file in a public place, who now faces a police investigation and possible loss of her licence.) Only other treatment providers are allowed to see the file, and only if the patient gives their express permission unless there is some kind of court order or emergency situation.

I think what happened to you is pretty damn unacceptable.