How do I hide Promote box from all except the seller.

Admin sorry I changed it to promote. The thing is seems everyone sees the promote box. I want to hide it from all but the seller just like the demo.

@Ogba
In file:
oc-content/plugins/osclass_pay/user/item_post.php

After following code:

  if(!isset($is_itempay)) {
    $is_itempay = 0;
  }

Add this:
  $hide = false;
  if(osc_is_ad_page()) {
    $item_full = Item::newInstance()->findByPrimaryKey($item_id);

    if(!osc_is_web_user_logged_in() || osc_item_user_id() <> osc_logged_user_id()) {
      $hide = true;
    }
  }

Then replace following code:
<div class="osp-promote-form <?php if(osc_get_osclass_location() == 'ajax' && osc_get_osclass_section() == 'runhook') { ?>osp-is-publish<?php } ?>">
with:
<div <?php if($hide) { ?>style="display:none!important;"<?php } ?> class="osp-promote-form <?php if(osc_get_osclass_location() == 'ajax' && osc_get_osclass_section() == 'runhook') { ?>osp-is-publish<?php } ?>">

Worked Perfectly. Thanks