How can I stop a process that is started from a windows service?

I am facing difficulty to stop a process that I have started from a service in another user session, basically the service will start a process once a user login/ unlock/ connect, this step works perfectly, after that I save the process information(id, etc) in order to be able later to close it via Process.CloseMainWindow().

My issue here is the process that I have started never get closed using the mentioned method, also, after checking the process id existence during the time of closing it is present, but when I checked for the process name it returns Idle.

Here is my code:

protected override void OnSessionChange(SessionChangeDescription sessionChangeDescription)
{
    try 
    {
        if (sessionChangeDescription.SessionId > 0) 
        { 
            var userInfo = TermServicesManager.GetSessionInfo(Dns.GetHostEntry("").HostName, sessionChangeDescription.SessionId);
            IPAddress ipAddress = new IPAddress(userInfo.ClientAddress.Address.Skip(2).Take(4).ToArray());

            if (!rdpSessionList.ContainsKey(sessionChangeDescription.SessionId))
            {
                onRdpSession.sessionId = sessionChangeDescription.SessionId;
                onRdpSession.ipAddress = ipAddress.ToString();
                onRdpSession.userName = userInfo.UserName;
                onRdpSession.sessionDateTime = DateTime.Now.ToString("yyyy'-'MM'-'dd'T'HH'-'mm'-'ss");
                onRdpSession.recordFileName = onRdpSession.generateRecordFileName();
            }
            else
            {
                onRdpSession = rdpSessionList[sessionChangeDescription.SessionId];
            }

            switch (sessionChangeDescription.Reason)
            {
                case SessionChangeReason.SessionLogon:
                case SessionChangeReason.RemoteConnect:
                case SessionChangeReason.SessionUnlock:
                    int processId = -1;
                    string filepath = AppDomain.CurrentDomain.BaseDirectory + "\\SessionFormRecorder.exe";
                    filepath = AppDomain.CurrentDomain.BaseDirectory;

                    RunInUserSession.StartProcessAsCurrentUser(onRdpSession.sessionId, "c:\\SessionFormRecorder.exe", null, null, false, processId);
                    onRdpSession.processId = processId;
                    WriteToFile("SessionChange" + DateTime.Now.ToLongTimeString() + ", SessionUnlock|RemoteConnect|SessionLogon [" + sessionChangeDescription.SessionId.ToString() + "]" + ", User: " + userInfo.UserName + ", Connect state: " + userInfo.ConnectState.ToString() + ", Client address: " + ipAddress.ToString() + ", user: " + userInfo.UserName + ", WinStationName: " + userInfo.WinStationName.ToString());
                            
                    break;

                case SessionChangeReason.SessionLock:
                case SessionChangeReason.SessionLogoff:
                case SessionChangeReason.RemoteDisconnect:
                    Process process = null;
                    process = Process.GetProcessById(onRdpSession.processId);
                    process.CloseMainWindow();
                    WriteToFile("SessionChange: " + onRdpSession.ToString() + ", Process name: " + process.ProcessName + ", " + DateTime.Now.ToLongTimeString() + " RemoteDisconnect|SessionLogoff|SessionLock [" + sessionChangeDescription.SessionId.ToString() + "]" + ", User: " + userInfo.UserName + ", Connect state: " + userInfo.ConnectState.ToString() + ", Client address: " + ipAddress.ToString() + ", user: " + userInfo.UserName + ", WinStationName: " + userInfo.WinStationName.ToString());
                    break;

                default:
                    break;
            }
        }
    } 
    catch(Exception ex)
    {
        WriteToFile("SessionChange exception: " + ex.Message + " || " + sessionChangeDescription.SessionId.ToString() + " || " + onRdpSession.sessionId.ToString());
    }
}