As you’ve probably seen, Let’s Encrypt certificates don’t contain any contact information for the subscriber whom the certificate identifies. Generally, all of the public information that’s available about the subscriber is already contained within the certificate.
ISRG, the organization that operates Let’s Encrypt, may have some kind of information about the person or entity that requested the certificate, such as IP addresses and e-mail addresses involved in that request. But ISRG can only disclose this information in response to a proper legal request such as a subpoena, not in response to a personal request.
If you think of all of these Internet infrastructure entities as analogous to something like the motor vehicle registration agency or the post office, you can see that they may have some kinds of personal information about suspects available, but they normally can’t disclose it directly to the victim of a crime without involving the courts or police first—and having an appropriate law enforcement entity make an appropriate formal request.
I’ve contacted the domain host through their abuse system.
Also found a IP address, but of course it’s from a VPS, I did contact the host and if there is any information available I will proceed with legal actions.