diff --git a/examples/disable_device.php b/examples/disable_device.php
new file mode 100755
index 0000000..f0cf0f9
--- /dev/null
+++ b/examples/disable_device.php
@@ -0,0 +1,50 @@
+<?php
+/**
+ * PHP API usage example
+ *
+ * contributed by: Art of WiFi
+ * description: example basic PHP script to disable/enable a device, returns true upon success
+ */
+
+/**
+ * using the composer autoloader
+ */
+require_once('vendor/autoload.php');
+
+/**
+ * include the config file (place your credentials etc. there if not already present)
+ * see the config.template.php file for an example
+ */
+require_once('config.php');
+
+/**
+ * the 24 character id of the device to disable/enable
+ */
+$device_id = '<enter the id of your device here>';
+
+/**
+ * the site to which the device belongs
+ */
+$site_id = '<enter your site id here>';
+
+/**
+ * initialize the UniFi API connection class and log in to the controller
+ */
+$unifi_connection = new UniFi_API\Client($controlleruser, $controllerpassword, $controllerurl, $site_id, $controllerversion);
+$set_debug_mode   = $unifi_connection->set_debug($debug);
+$loginresults     = $unifi_connection->login();
+
+/**
+ * then we disable the device
+ */
+$disable_result = $unifi_connection->disable_ap($device_id, true);
+
+/**
+ * or we enable the device, uncomment as neccesary (then also comment the previous call)
+ */
+//$disable_result = $unifi_connection->disable_ap($device_id, false);
+
+/**
+ * provide feedback (the newly created voucher code, without the dash) in json format
+ */
+echo json_encode($disable_result, JSON_PRETTY_PRINT);
diff --git a/src/Client.php b/src/Client.php
index ddd6dd2..6f65053 100755
--- a/src/Client.php
+++ b/src/Client.php
@@ -1275,7 +1275,7 @@ public function set_ap_radiosettings($ap_id, $radio, $channel, $ht, $tx_power_mo
      */
     public function set_ap_wlangroup($wlantype_id, $device_id, $wlangroup_id) {
         if (!$this->is_loggedin) return false;
-        if (in_array($wlantype_id, ['ng', 'na'])) return false;
+        if (!in_array($wlantype_id, ['ng', 'na'])) return false;
         $json     = json_encode(['wlan_overrides' => [],'wlangroup_id_'.$wlantype_id => $wlangroup_id]);
         $response = $this->exec_curl('/api/s/'.$this->site.'/upd/device/'.trim($device_id),'json='.$json);
         return $this->process_response_boolean($response);
@@ -1550,7 +1550,7 @@ public function delete_wlan($wlan_id)
      */
     public function set_wlan_mac_filter($wlan_id, $mac_filter_policy, $mac_filter_enabled, array $macs)
     {
-        if (in_array($mac_filter_policy, ['allow', 'deny'])) return false;
+        if (!in_array($mac_filter_policy, ['allow', 'deny'])) return false;
         $payload                     = (object)[];
         $payload->mac_filter_enabled = (bool)$mac_filter_enabled;
         $payload->mac_filter_policy  = $mac_filter_policy;