diff --git a/whmcs.class.php b/whmcs.class.php
index 78d4a5b..574e353 100644
--- a/whmcs.class.php
+++ b/whmcs.class.php
@@ -26,7 +26,7 @@ public function __construct($url = 'http://whmcs.com/include/api.php', $username
 	public function authenticate($username, $password){
 		$response = $this->api("validatelogin", array("email" => $username, "password2" => $password));
 		if($response->userid){
-			return true;
+			return $response->userid; // Same as returning true
 		}
 
 		return false;
@@ -126,6 +126,28 @@ public function getDomainWHOIS($domainId){
 		return $response;
 	}
 
+    /**
+     * Get product groups - Custom API
+     * @param int $gid
+     * @return object
+     * @throws WhmcsException
+     */
+    public function getProductsGroups($gid = 0){
+        $params = array();
+
+        if($gid > 0){
+            $params['gid'] = $gid;
+        }
+
+        $response = $this->api("getproductgroups", $params);
+
+        if($response->result == 'error'){
+            throw new WhmcsException("WHMCS complained: ".$response->message);
+        }
+
+        return $response;
+    }
+
         /**
          * Get products
          * @param int $pid
@@ -136,6 +158,8 @@ public function getDomainWHOIS($domainId){
          * @link http://docs.whmcs.com/API:Get_Products
          */
 	public function getProducts($pid = 0, $gid = 0, $module = null){
+	    $params = array();
+
 		if($pid > 0){
 			$params['pid'] = $pid;
 		}
@@ -176,7 +200,7 @@ public function getServices($uid = 0, $serviceId = 0, $domain = '', $productId =
 		}
 
 		$params['limitnum'] = $limit;
-		$params['limitstart'] = $limitstart;
+		//$params['limitstart'] = $limitstart; // TODO: Unused variable
 
 		if($uid > 0){
 			$params['clientid'] = $uid;
@@ -217,6 +241,8 @@ public function getServices($uid = 0, $serviceId = 0, $domain = '', $productId =
          * @link http://docs.whmcs.com/API:Get_Transactions
          */
 	public function getTransactions($uid = 0, $invoiceId = 0, $transactionId = 0){
+        $params = array();
+
 		if($uid > 0){
 			$params['clientid'] = $uid;
 		}
@@ -284,6 +310,8 @@ public function getEmails($uid, $filter = '', $filterdate = '', $start = 0, $lim
          * @link http://docs.whmcs.com/API:Add_Credit
          */
 	public function addCredit($data){
+        $credit = array();
+
 		$attributes = array("clientid", "description", "amount");
 
 		foreach($attributes as $k){
@@ -305,7 +333,7 @@ public function addCredit($data){
 
         /**
          * Get Credits
-         * @param id $uid
+         * @param int $uid
          * @return object
          * @link http://docs.whmcs.com/API:Get_Credits
          */
@@ -350,7 +378,9 @@ public function updateClient($uid = 0, $update){
          */
 	public function addClient($data){
 		$attributes = array("firstname", "lastname", "companyname", "email", "address1", "address2", "city", "state", "postcode", "country", "phonenumber", "password2", "currency", "clientip", "language", "groupid", "securityqid", "securityqans", "notes", "cctype", "cardnum", "expdate", "startdate", "issuenumber", "customfields", "noemail", "skipvalidation");
-	
+
+        $customer = array();
+
 		foreach($attributes as $k){
 			$customer[$k] = $data[$k];
 		}
@@ -408,6 +438,8 @@ public function getClient($uid = 0, $email = ''){
 	public function addContact($data){
 		$attributes = array("clientid", "firstname", "lastname", "companyname", "email", "address1", "address2", "city", "state", "postcode", "country", "phonenumber", "password2", "permissions", "generalemails", "productemails", "domainemails", "invoiceemails", "supportemails", "skipvalidation");
 
+        $contact = array();
+
 		foreach($attributes as $k){
 			$contact[$k] = $data[$k];
 		}
@@ -486,13 +518,15 @@ public function createInvoice($data){
 			"taxrate", "taxrate2", "notes", "sendinvoice",
 			"autoapplycredit");
 
+        $params = array();
+
 		foreach($attributes as $a){
 			if(!empty($params[$a])){
 				$params[$a] = $data[$a];
 			}
 		}
 
-		for($i = 0; $i < count($data['items']; $i++)){
+		for($i = 0; $i < count($data['items']); $i++){
 			$params['itemdescription' . $i] = $data['items'][$i]['description'];
 			$params['itemamount' . $i] = $data['items'][$i]['amount'];
 			$params['itemtaxed' . $i] = $data['items'][$i]['taxed'];
@@ -557,7 +591,7 @@ public function getOrders($uid = 0, $orderId = 0, $status = '', $start = 0, $lim
 		}
 
 		if($orderId > 0){
-			$params['id'] = $invoiceId;
+			$params['id'] = $orderId;
 		}
 
 		if($status == "Pending" || $status == "Active" || $status == "Fraud" || $status == "Cancelled"){
@@ -695,6 +729,8 @@ public function acceptOrder($orderid, $serverid = null, $serviceusername = null,
          * @link http://docs.whmcs.com/API:Get_Stats
          */
 	public function getStats(){
+	    $params = array();
+
 		$response = $this->api("getstats", $params);
 
 		if($response->result == 'error'){
diff --git a/whmcs/includes/api/getproductgroups.php b/whmcs/includes/api/getproductgroups.php
new file mode 100644
index 0000000..751e38d
--- /dev/null
+++ b/whmcs/includes/api/getproductgroups.php
@@ -0,0 +1,49 @@
+<?php
+use Illuminate\Database\Capsule\Manager as Capsule;
+
+function get_env($vars)
+{
+    $array = array('action' => array(), 'params' => array());
+    if (isset($vars['cmd'])) {
+        //Local API mode
+        $array['action'] = $vars['cmd'];
+        $array['params'] = (object)$vars['apivalues1'];
+        $array['adminuser'] = $vars['adminuser'];
+
+    } else {
+        //Post CURL mode
+        $array['action'] = $vars['_POST']['action'];
+        unset($vars['_POST']['username']);
+        unset($vars['_POST']['password']);
+        unset($vars['_POST']['action']);
+        $array['params'] = (object)$vars['_POST'];
+    }
+    return (object)$array;
+}
+
+try {
+    $vars = get_defined_vars();
+    //Get the parameters
+    $request = get_env($vars);
+
+    $gid = (int)$request->params->gid;
+
+    if ($gid)
+        $productGroups = Capsule::table('tblproductgroups')->where('id', $gid)->get();
+    else
+        $productGroups = Capsule::table('tblproductgroups')->get();
+
+    if (count($productGroups))
+        $apiresults = array(
+            "result" => "success",
+            "productGroups" => $productGroups
+        );
+    else
+        $apiresults = array(
+            "result" => "error",
+            "message" => 'There are no product groups'
+        );
+} catch (Exception $e) {
+    $apiresults = array("result" => "error", "message" => $e->getMessage());
+}
+?>
\ No newline at end of file