/**
  * Delete an Invoice from InfusionSoft
  */
 private function _delete_infusion_invoice($invoiceId)
 {
     // Add or Get buyer from InfusionSoft
     require_once app_path() . "/libraries/infusionsoft/isdk.php";
     // Add InfusionSoft Library
     $isapp = new iSDK();
     if ($isapp->cfgCon("comissionTracker")) {
         $result = $isapp->deleteInvoice($invoiceId);
         return $result;
     }
 }