Fix bugs in marketing controller

app/Http/Controllers/DS/MarketingController.php

 		foreach($subDetail as $a)
 		{
 			$var1="";
+			$contractor_name="";
 			if(empty($a->WorkOrder)){}
 			else	
 			{
 				if(!empty($staff))
 				{
 					$var1 =$staff->name;
-				}		
+				}
+				
+				if(!empty($contractor))
+				{
+					$contractor_name =$contractor->name;
+				}	
 
 				$reg_time = $a->created_at;
 				$expiry_date = $reg_time->addDays(3);    
 						'customer_building' => $building,
 						'customer_postcode' => $a->Subscriber->postcode,
 						'customer_city' => $a->Subscriber->city,
-						'contractor_id' => $contractor->name,
+						'contractor_id' => $contractor_name,
 						'installer_id' => $var1,
 						'dateTimeEnd' => $a->WorkOrder->dateTimeEnd,
 						'status' => $a->WorkOrder->status,