public function delete()
 {
     //init controller data
     $this->extensions->hk_InitData($this, __FUNCTION__);
     $custom_block_id = (int) $this->request->get['custom_block_id'];
     $layout = new ALayoutManager();
     if (!$layout->deleteCustomBlock($custom_block_id)) {
         $this->session->data['warning'] = $this->language->get('error_delete');
     } else {
         $this->session->data['success'] = $this->language->get('text_success_deleted');
     }
     //update controller data
     $this->extensions->hk_UpdateData($this, __FUNCTION__);
     $this->redirect($this->html->getSecureURL('design/blocks'));
 }
<?php

if (!defined('DIR_CORE')) {
    header('Location: static_pages/');
}
// delete block
$lm = new ALayoutManager();
$lm->deleteBlock('default_pp_express_button');
$lm->deleteBlock('default_pp_express_banner');
$block_names = array('paypal_billmelater_marketing');
$custom_blocks = $lm->getBlocksList(array('subsql_filter' => 'cb.custom_block_id <> 0'));
foreach ($custom_blocks as $block) {
    if (in_array($block['block_name'], $block_names)) {
        $this->db->query("DELETE FROM " . DB_PREFIX . "block_layouts\n\t\t\t\t\t\t   WHERE custom_block_id = '" . (int) $block['custom_block_id'] . "'");
        $this->cache->delete('layout.a.blocks');
        $this->cache->delete('layout.blocks');
        $lm->deleteCustomBlock($block['custom_block_id']);
    }
}
$rm = new AResourceManager();
$rm->setType('image');
$resources = $rm->getResources('extensions', 'default_pp_express');
if (is_array($resources)) {
    foreach ($resources as $resource) {
        $rm->deleteResource($resource['resource_id']);
    }
}