CPA leaked tax return details

A CPA that is supposedly working on my Tax application accidentally has uploaded some other people tax applications to my account on their "secured" platform.
Now I am very worried that they might have done something similar with my private information. And the fact that they are not returning my emails adds to the problem.
Since I have no confidence in them being able to handle my private data I would like to request them to delete every single bit of information connected with my application. Is there standard official way of requesting it to make sure that they are legally bound to remove everything from their system.
Additionally are they legally required to tell me that my data was accidentally leaked ?
There are laws around reporting data breaches and security incidents, not sure if any of that applies here.