diff --git a/README.md b/README.md
index a030dc2..4af16fe 100644
--- a/README.md
+++ b/README.md
@@ -44,9 +44,10 @@ topic::queue1;topic::queue2  <-- will read from queue1 and queue2 on the topic
 
 Subscribing with client acknowledgement option (ENV variables):
 
-STOMP_CONSUMER_WIN_SIZE=1024        // number of bytes that Broker will send to client before it expects ACK
+```
+STOMP_CONSUMER_WIN_SIZE=819200      // number of bytes that Broker will send to client before it expects ACK
 STOMP_CONSUMER_ACK_MODE=client		// mode: client (ACK needs to be sent) | auto (no ACK, and window-size has to be -1 in that case)
-
+```
 
 You can see all other available ``.env`` variables, their defaults and usage explanation within 
 the [config file](config/stomp.php). 
diff --git a/config/stomp.php b/config/stomp.php
index c02d96c..c37d231 100644
--- a/config/stomp.php
+++ b/config/stomp.php
@@ -78,7 +78,7 @@
      * Once that happens the client will not receive any more messages until it sends the appropriate ACK or NACK
      * frame for the messages it already has.
      */
-    'consumer_window_size' => env('STOMP_CONSUMER_WIN_SIZE', 1048576),
+    'consumer_window_size' => env('STOMP_CONSUMER_WIN_SIZE', 819200),
 
     /**
      * Subscribe mode: auto, client.
diff --git a/src/Queue/Jobs/StompJob.php b/src/Queue/Jobs/StompJob.php
index 2475e01..1d01992 100644
--- a/src/Queue/Jobs/StompJob.php
+++ b/src/Queue/Jobs/StompJob.php
@@ -4,6 +4,7 @@
 
 use Asseco\Stomp\Queue\Stomp\Config;
 use Asseco\Stomp\Queue\StompQueue;
+use Illuminate\Broadcasting\BroadcastEvent;
 use Illuminate\Container\Container;
 use Illuminate\Contracts\Queue\Job as JobContract;
 use Illuminate\Queue\Jobs\Job;
@@ -112,13 +113,36 @@ public function fire()
 
     protected function isNativeLaravelJob(): bool
     {
-        return array_key_exists('job', $this->payload);
+        $job = Arr::get($this->payload, 'job');
+
+        return $job && str_contains($job, 'CallQueuedHandler@call');
+    }
+
+    protected function laravelJobClassExists(): bool
+    {
+        $eventClassName = Arr::get($this->payload, 'displayName');
+        if ($eventClassName) {
+            return class_exists($eventClassName);
+        } else {
+            $command = Arr::get($this->payload, 'data.command');
+            $command = $command ?? unserialize($command);
+            /** @var BroadcastEvent $command */
+            if ($command & $command->event && class_exists(get_class($command->event))) {
+                return true;
+            }
+        }
+
+        return false;
     }
 
     protected function fireLaravelJob(): void
     {
-        [$class, $method] = JobName::parse($this->payload['job']);
-        ($this->instance = $this->resolve($class))->{$method}($this, $this->payload['data']);
+        if ($this->laravelJobClassExists()) {
+            [$class, $method] = JobName::parse($this->payload['job']);
+            ($this->instance = $this->resolve($class))->{$method}($this, $this->payload['data']);
+        } else {
+            $this->log->error("$this->session [STOMP] Laravel job class does not exist!");
+        }
     }
 
     protected function fireExternalJob(): void
@@ -241,8 +265,6 @@ protected function failed($e)
 
     protected function ackIfNecessary()
     {
-        if (Config::get('consumer_ack_mode') == StompQueue::ACK_MODE_CLIENT && $this->frame) {
-            $this->stompQueue->client->ack($this->frame);
-        }
+        $this->stompQueue->ackLastFrameIfNecessary();
     }
 }
diff --git a/src/Queue/StompQueue.php b/src/Queue/StompQueue.php
index c1de818..9782dfe 100644
--- a/src/Queue/StompQueue.php
+++ b/src/Queue/StompQueue.php
@@ -363,10 +363,13 @@ public function pop($queue = null)
 
         if (!$queueFromFrame) {
             $this->log->error("$this->session [STOMP] Wrong frame received. Expected MESSAGE, got: " . print_r($frame, true));
+            $this->_lastFrame = null;
 
             return null;
         }
 
+        $this->_lastFrame = $frame;
+
         return new StompJob($this->container, $this, $frame, $queueFromFrame);
     }
 
@@ -500,7 +503,7 @@ protected function subscribeToQueues(): void
                 continue;
             }
 
-            $winSize = Config::get('consumer_window_size') ?? 512000;
+            $winSize = Config::get('consumer_window_size') ?? 819200;
             if ($this->_ackMode != self::ACK_MODE_CLIENT) {
                 $winSize = -1;
             }
@@ -521,7 +524,7 @@ protected function subscribeToQueues(): void
      *
      * @return void
      */
-    protected function ackLastFrameIfNecessary()
+    public function ackLastFrameIfNecessary()
     {
         if ($this->_ackMode == self::ACK_MODE_CLIENT && $this->_lastFrame) {
             $this->client->ack($this->_lastFrame);