How do I block a stolen iPhone using its serial number and IMEI?

Hello, dear tech support. My name is Vladimir and I have been a long-time fan of your technology since 2012. Understanding the complexity of the current political situation, I still want to contact you, because I am in despair. My phone was stolen, the locator was disabled because I was preparing it for sale. The dishonest buyer simply ran away with it. I can confirm that the phone is mine with a receipt of purchase, I will attach a photo to the letter. 

Please mark this phone as stolen and block it. 

You are the only hope left. There is a complaint to the police. 

16 Pro Max 512 Gb, black. 

Serial number: G*******K 

IMEI: ****************

[Edited by Moderator]