How can I report an engine user?

I have analysed couple of games with Shredder and it turns out that some people I played made the same move suggested by the engine. And not just 1 move (which could be a fluke) , but rather 20-25 in a row. Funny thing is that some of these players played a very poor opening and I was sure to win, only to find out that their play suddenly increased to a Master level. What a weird cohincedence, right? 

Please let me know where I can report these people. And don't tell me there is no such thing as "reporting" cheater, because that would mean that you have no interest in fighting them.

I found a group called cheating forum and you should be able to report there.

where is it?

OK so here's the forum.  You have to apply for membership.  So good for discussions, not so good for reporting.

http://www.chess.com/groups/home/cheating-forum

Here's an article on cheating: Second paragraph for a report link.

https://support.chess.com/customer/portal/articles/1444879

Naming and shaming is not allowed on  forums.

You don't need to be a member of the cheating forum. Send a message to staff here:

https://support.chess.com/customer/portal/emails/new