Richard, I think we know by now that there is a limit to the amount of policing work from the administrators. Many trolls do not show any tell tale signs simply because they won't post anything on italki's public forums. Instead, they are only interested in sending private messages to their prey. And I think it takes two hands to clap: I've come across members who have requested for "language partners" and used suggestive pictures. This is like someone holding a neon signboard and flailing their arms at the trolls. When there is a demand, there is a supply. It does upset me that these trolls and "trollees" are abusing an educational site for purposes other than learning a language and exchanging views in mutually respectful ways.

Having been here for a couple of years, I know it's an old problem that won't go away anytime soon. After a while, I realised I have acquired a "raydar" for detecting trolls. They emit a certain "smell". For example, it could be an incredibly unbelievable stat that I have received from someone recently:  "I am an America working in a university in United State." (yes, the blatant errors are intended) or someone who claims that she lives in France, is born in Indonesia but speaks neither French nor Bahasa Indonesia. The most definitive smell would be emitted when they start providing their Skype ID or ask you for your WhatsApp number. 

So, as pertinent as it is to purge these fellas by reporting them (and keeping our fingers crossed that the administrators will do something), we have to be discerning and hone our sense of smell. Give them a zero possibility of doing their shenanigans by disengaging them. Remove what they enjoy most: attention and room for manoeuvre. No supply, no demand. 

Richard, I appreciate your bringing up this topic. An upvote for you, Sir! 

Alice,

Italki can block the original ISP, but if the person uses a VPN, forget it!

Tet...

If the piece of garbage contacted you on italki, then he must have an italki account and profile.

If you find his profile you can then click on "flag" and describe what happended to italki (Don't worry, no one can see the message you send to italki support).

Here is how to block someone on Skype:   https://support.skype.com/en/faq/fa34809/how-do-i-block-unblock-or-report-someone-in-skype-on-desktop

Thank you for sharing your unfortunate experience with us.
I hope you don't experience this kind of problem again.