How to write an . xlsx file permanently, using the Closedxml library?

Question

When you run the code for simulation, you notice that it is changing the file test.xlsx as expected, however, when closing the execution it does not save the changes as, when running the program again it will start a new file and will not pull the already changed base.

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public partial class Form1 : Form
{
    
    public Form1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        using (var workbook = new XLWorkbook())
        {
            string DataEmprestimo;
            string DataDevolucao;
            var row = 1;
            var col = 1;
            var linha = row;
            var coluna = col;
            int cont = 2;

            var planilha = workbook.Worksheets.Add("Planilha1");

            planilha.Cell(linha, coluna).Value = "Equipamento";
            var range = planilha.Range("A1"); 
            range.Merge().Style.Font.SetBold().Font.FontSize = 12;
            planilha.Columns().AdjustToContents();

            linha = linha + 1;

            for (cont = 2; cont <= 20000; cont++)
            {
                var Equipamento = planilha.Cell("A" + cont.ToString()).Value.ToString();
                if (string.IsNullOrEmpty(Equipamento) == true)
                {
                    linha = cont;
                    planilha.Cell(linha, coluna).Value = textBox1.Text;
                    
                    break;
                }
            }
            /*
            while (true)
            {
                var Equipamento = planilha.Cell("A" + linha.ToString()).Value.ToString();
                
                if (string.IsNullOrEmpty(Equipamento))
                {
                    break;
                }

            }
            */
            
            planilha.Cell("B3").Value = textBox2.Text;
            planilha.Cell("C2").Value = textBox3.Text;
            planilha.Cell("D2").Value = textBox4.Text;
            planilha.Cell("E2").Value = textBox5.Text;
            planilha.Cell("F2").Value = textBox6.Text;
            planilha.Cell("G2").Value = textBox7.Text;

            DataEmprestimo = CalEmp.SelectionRange.Start.ToShortDateString();
            planilha.Cell("H2").Value = DataEmprestimo;

            
            DataDevolucao = CalDev.SelectionRange.Start.ToShortDateString();
            planilha.Cell("I2").Value = DataDevolucao;



            MessageBox.Show("Equipamento cadastrado");
            workbook.SaveAs(@"c:\data\teste.xlsx");

            //Process.Start(new ProcessStartInfo(@"c:\data\teste.xlsx") { UseShellExecute = true });
            workbook.Dispose();
            
            
        }

        
    }

    private void groupBox1_Enter(object sender, EventArgs e)
    {
        
    }

    private void btnSair_Click(object sender, EventArgs e)
    {
        Close();
    }

    private void button2_Click(object sender, EventArgs e)
    {
        Process.Start(new ProcessStartInfo(@"c:\data\teste.xlsx") { UseShellExecute = true });
    }
}