Where is topic where i cant ban player for verbal abuse?

You need to fill out a support ticket, try to avoid posting the in-game name of other players on the forums.

At the top of the page you'll see "Support" on the right, click that, then on the next page over on the right you'll see "Web Form", click that. Then on the next page from the drop-down options select "Game-Related: Crossfire". Then "Category: Complaints". Then in the "Question" text box proceed to tell them about what happened including the in-game name of the player. Below that text box is a box you can click to upload a file of the screenshot, it has to be in one of a number of formats including .gif and .jpg. Normally when you save a screenshot in Crossfire it is a bitmap, so you'll need to convert the file to a format that they'll accept.

Send in a Support Ticket regarding the verbal abuse. Be sure to include multiple screenshots, and any necessary information about the player.