What to do , if I want to make a report against any member in mylot?

Well, your experience between you and this other user are a matter between you, the other user and the administration, so I wouldn't go sharing it in a discusion. If it is an issue of this user stalking and making threats in email, remove him from your friends list and contact mylot admins....if it is abusive threads, if he is trolling you and such, report each thread he posts, each response he posts, they will be deleted and if it continues, he will probably be banned.

Yes, you must report to the admin using the "contact" form.