If someone posted, without your permission, the contents of a private message you sent to him, and identified you as the source of that content, then that is a violation. That's my interpretation of the rules.
I would send all information concerning the private information to an Admin in a PM, complete with a copy paste of the PM you sent, and links showing where that information was divulged by the recipient.
The main thing is, only an Admin can help you.
Step aside son, you're blockin' the MOMO! ... .. Disproving absence of evidence should be easy, show the evidence of.