diff --git a/src/Portalum.Zvt.TerminalSimulator/Program.cs b/src/Portalum.Zvt.TerminalSimulator/Program.cs
index 6009416..dd299f0 100644
--- a/src/Portalum.Zvt.TerminalSimulator/Program.cs
+++ b/src/Portalum.Zvt.TerminalSimulator/Program.cs
@@ -1,5 +1,6 @@
 using Portalum.Zvt.Helpers;
 using SuperSimpleTcp;
+using System.Runtime.CompilerServices;
 
 class Program
 {
@@ -37,6 +38,17 @@ private static void Events_ClientDisconnected(object? sender, ConnectionEventArg
         Console.WriteLine($"ClientDisconnected - {e.IpPort}");
     }
 
+    private static bool IsClientConnected(string ipPort)
+    {
+        if (_tcpServer == null)
+        {
+            return false;
+        }
+
+        var clients = _tcpServer.GetClients();
+        return clients.Contains(ipPort);
+    }
+
     private static void Events_DataReceived(object? sender, DataReceivedEventArgs e)
     {
         if (_tcpServer == null)
@@ -76,6 +88,8 @@ private static void Events_DataReceived(object? sender, DataReceivedEventArgs e)
         //Authorization (06 01)
         if (data.StartsWith(new byte[] { 0x06, 0x01 }))
         {
+            //Step 1
+
             var amountBytes = data.Slice(4);
             var amount = NumberHelper.BcdToDecimal(amountBytes.ToArray());
 
@@ -83,24 +97,53 @@ private static void Events_DataReceived(object? sender, DataReceivedEventArgs e)
 
             Thread.Sleep(500);
 
+            if (!IsClientConnected(e.IpPort))
+            {
+                Console.WriteLine("Failure - Client is not connected");
+                return;
+            }
+
             Console.WriteLine("Send Command Completion");
             _tcpServer.Send(e.IpPort, _commandCompletionPackage);
 
             Thread.Sleep(1000);
 
+            // Step 2
+
+            if (!IsClientConnected(e.IpPort))
+            {
+                Console.WriteLine("Failure - Client is not connected");
+                return;
+            }
+
             Console.WriteLine("Send Message - Insert Card");
             var waitForCardMessage = new byte[] { 0x04, 0xFF, 0x01, 0x0A };
             _tcpServer.Send(e.IpPort, waitForCardMessage);
 
             Thread.Sleep(2000);
 
+            // Step 3
+
+            if (!IsClientConnected(e.IpPort))
+            {
+                Console.WriteLine("Failure - Client is not connected");
+                return;
+            }
+
             Console.WriteLine("Send Status-Information");
             var byteData = new byte[] { 0x04, 0x0F, 0x77, 0x27, 0x00, 0x04, 0x00, 0x00, 0x00, 0x00, 0x20, 0x40, 0x0B, 0x00, 0x04, 0x70, 0x0C, 0x22, 0x39, 0x53, 0x0D, 0x10, 0x06, 0x0E, 0x25, 0x12, 0x17, 0x00, 0x01, 0x19, 0x70, 0x22, 0xF0, 0xF8, 0xEE, 0xEE, 0xEE, 0xEE, 0xEE, 0xEE, 0x47, 0x71, 0x29, 0x28, 0x00, 0x48, 0x69, 0x2A, 0x31, 0x30, 0x30, 0x34, 0x36, 0x31, 0x37, 0x36, 0x33, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x3B, 0x36, 0x31, 0x31, 0x38, 0x30, 0x34, 0x00, 0x00, 0x3C, 0xF0, 0xF1, 0xF4, 0x47, 0x45, 0x4E, 0x2E, 0x4E, 0x52, 0x2E, 0x3A, 0x36, 0x31, 0x31, 0x38, 0x30, 0x34, 0x49, 0x09, 0x78, 0x87, 0x04, 0x70, 0x88, 0x00, 0x04, 0x70, 0x8A, 0x2E, 0x8B, 0xF1, 0xF7, 0x44, 0x65, 0x62, 0x69, 0x74, 0x20, 0x4D, 0x61, 0x73, 0x74, 0x65, 0x72, 0x63, 0x61, 0x72, 0x64, 0x00 };
             _tcpServer.Send(e.IpPort, byteData);
 
-
             Thread.Sleep(1000);
 
+            // Step 4
+
+            if (!IsClientConnected(e.IpPort))
+            {
+                Console.WriteLine("Failure - Client is not connected");
+                return;
+            }
+
             Console.WriteLine("Send Completion");
             _tcpServer.Send(e.IpPort, _completionPackage);