diff --git a/src/Service/WarrantyBulkUploader.php b/src/Service/WarrantyBulkUploader.php
index fec7b657..7ebb3278 100644
--- a/src/Service/WarrantyBulkUploader.php
+++ b/src/Service/WarrantyBulkUploader.php
@@ -41,6 +41,8 @@ class WarrantyBulkUploader
 
     protected $em;
     protected $batt_hash;
+    protected $serial_hash;
+    protected $sap_batt_hash;
     
     public function __construct(EntityManagerInterface $em)
     {
@@ -52,6 +54,9 @@ class WarrantyBulkUploader
         // hash the battery table using sap_code as index
         $this->populateBatteryIndex();
 
+        // hash the sap battery table
+        $this->populateSAPBatteryIndex();
+
         // attempt to open file
         try
         {
@@ -154,7 +159,7 @@ class WarrantyBulkUploader
         $warr_tnv = $batt_info['warr_tnv'];
 
         // format purchase date to DateTime and then change the format to Y-m-d
-        $purchase_date = DateTime::createFromFormat('m/d/y', $date_purchase);
+        $purchase_date = DateTime::createFromFormat('d-M-y', $date_purchase);
 
         // need to manually create the created date
         $date_create = date('Y-m-d H:i:s');
@@ -174,6 +179,10 @@ class WarrantyBulkUploader
         $last_name = addslashes($lname);
         $mobile_number = addslashes($mobile);
 
+        // TODO: add checking for sap code in sap battery hash
+        // if it exists in sap battery hash, we insert sap_code in warranty
+        // if not, we insert NULL in its place.
+
         // populate the values string for the values to be inserted into warranty
         $value_string = '(' . $model_id . ',' . $size_id . ',\'' . $sap_code . '\',\'' . $serial . '\',\'' . $warranty_class . '\',\''
                         . $plate_number . '\',\'' . WarrantyStatus::ACTIVE . '\',\'' . $date_create . '\',\'' . $str_date_purchase
@@ -238,10 +247,10 @@ class WarrantyBulkUploader
             return $errors;
         }
 
-        $purchase_date = DateTime::createFromFormat('m/d/y', $date_purchase);
+        $purchase_date = DateTime::createFromFormat('d-M-y', $date_purchase);
         if ($purchase_date === false)
         {
-            $message = 'Invalid date format. Date format should be: m/d/y (example: 06/13/16)';
+            $message = 'Invalid date format. Date format should be: dd-mmm-yyyy (example: 06-Jun-16)';
             $errors = $this->setOutputInfo($fields, 'NOT UPLOADED', $message, $row_num);
             return $errors;
         }
@@ -307,6 +316,17 @@ class WarrantyBulkUploader
             return $errors;
         }
 
+        // check if serial is a duplicate of serial within the file
+        // add serial to hash, in case csv file has duplicate serials in it.
+        if (!isset($this->serial_hash[$serial]))
+            $this->serial_hash[$serial] = $serial;
+        else
+        {
+            $message = 'Duplicate serial in file.';
+            $errors = $this->setOutputInfo($fields, 'NOT UPLOADED', $message, $row_num);
+            return $errors;
+        }
+
         return $errors;
     }
 
@@ -413,6 +433,27 @@ class WarrantyBulkUploader
         }
     }
 
+    protected funciton populateSAPBatteryIndex()
+    {
+        $conn = $this->em->getConnection();
+
+        // get all the sap batteries
+        $sql = 'SELECT sap.id, sap.brand_id, sap.size_id FROM sap_battery sap';
+        $stmt = $conn->prepare($sql);
+        $stmt->execute();
+
+        $results = $stmt->fetchAll();
+
+        // go through the rows
+        foreach ($results as $row)
+        {
+            $this->sap_batt_hash[$row['id']] = [
+                'sap_brand' => $row['brand_id'],
+                'sap_size' => $row['size_id'],
+            ];
+        }
+    }
+
     protected function cleanPlateNumber($plate)
     {
         return strtoupper(str_replace(' ', '', $plate));