Domain blocked in adsense, how to find out the reason?

Question

contextual advertising

The *.ru domain was blocked in the adsense service, and advertising on the version of the site for another region works with the *.kz domain. Worked with adsense for many years, no complaints.
adsense support says:

Thank you for your contact.
Your *.ru web resource has been included in the list of sites that violate intellectual property rules. Moreover, the site was blacklisted not at the initiative of Google, but at the request of an official institution, so if you want to return the display of ads, you should read the message about violations and correct them (delete individual pages on the site).
If you need help, please contact us.
Sincerely,

There were no letters and notifications anywhere, the support ignores further.
How to find out who filed a complaint, pages, name of legal entity. faces. Or is it unrealistic, can anyone come across? Can I send a question by regular letter notarized to them?
The content of the site is absolutely white and legal.
Thank you.

Answer 1

there are notifications in the adsense interface itself

Answer 2

What information is in the Account - Program Rules tab?
It's probably a DMCA violation. In this case, there is little that can be done.