This is at least some kind of forward movement! 

When I corresponded with support, I did not provide them with such extended personal data.
 
In the correspondence, I referred to the fact that their service is not an organization to which the authorized government authorities of the jurisdiction in which they are registered have delegated and obliged to collect extended personal data of clients. 
My second argument was that I considered it unacceptable for myself to send my extended personal data to such an unauthorized organization. 
Further, I indicated that the support was provided with my personal data in the form of my email address, which I consider to be limited by KYC and quite sufficient to solve the problem. 
I also indicated that I was afraid of personal data being leaked and used for marketing purposes. 
In my case, this worked positively and they no longer wrote to me about the need to provide them with such personal data in the form of extended KYC. 

They solved my problem after about 10-12 letters.

But, probably, you will decide for yourself what you should do with the issue of providing support with verification data for the KYC procedure.   Or maybe try to maintain confidentiality.