Invalid Column Name SQL Server

Question

Whenever I submit my form, it gives me an error code:

"invalid column name" for all of the eventspecialist, phone, phon2, etc. and @SPECIALIST, @CUST_PHONE, @CUST_PHONE2, etc.

Here is my code below, perhaps I'm not writing the SQL statement or parameters correctly? The ones with @ infront are what's in my database, and the other lowercase ones are my textboxes. I'm relatively new to this type of coding.

Edit: Changed my INSERT INTO statement to what was suggested. The error still persists, but is only minimized to

"Invalid column name eventspecialist, Invalid column name phone, Invalid column name phone2, etc."

private void execution(string eventspecialist, string phone, string phone2, string firstname, string lastname, string besttime, string companyname, string nonprofit, string requesteddate, string requestedtime, string attendance, string eventtype, string other, string leadsource, string notes, string catering, string bar, string damagedeposit, string dancefloor, string griddate, string gridnotes, string comments)
{
    SqlConnection conn = new SqlConnection(GetConnectionString());

    string sql = "INSERT INTO tblcontacts (@SPECIALIST, @CUST_PHONE1, @CUST_PHONE2, @CUST_FNAME, @CUST_LNAME, @BEST_TIME, @COMPANY_NAME, @NONPROFIT, @REQ_DATE, @REQ_TIME, @ATTENDANCE, @EVENT_TYPE, @OTHER_DESC, @LEAD_SOURCE, @NOTES, @CATERING, @BAR, @DAMAGE_DEPOSIT, @DANCE_FLOOR) VALUES (eventspecialist, phone, phone2, firstname, lastname, besttime, companyname, nonprofit, requesteddate, requestedtime, attendance, eventtype, other, leadsource, notes, catering, bar, damagedeposit, dancefloor)";
    string sql2 = "INSERT INTO tblnotes (@NOTEDATE, @NOTEBY, @COMMENTS) VALUES (griddate, gridnotes, comments)";

    try
    {
        conn.Open();
        SqlCommand cmd = new SqlCommand(sql, conn);

        cmd.Parameters.Add("@SPECIALIST", SqlDbType.NVarChar, 50).Value = eventspecialist;
        cmd.Parameters.Add("@CUST_PHONE1", SqlDbType.NVarChar, 50).Value = phone;
        cmd.Parameters.Add("@CUST_PHONE2", SqlDbType.NVarChar, 50).Value = phone2;
        cmd.Parameters.Add("@CUST_FNAME", SqlDbType.NVarChar, 50).Value = firstname;
        cmd.Parameters.Add("@CUST_LNAME", SqlDbType.NVarChar, 50).Value = lastname;
        cmd.Parameters.Add("@BEST_TIME", SqlDbType.NVarChar, 50).Value = besttime;
        cmd.Parameters.Add("@COMPANY_NAME", SqlDbType.NVarChar, 225).Value = companyname;
        cmd.Parameters.Add("@NONPROFIT", SqlDbType.NVarChar, 10).Value = nonprofit;
        cmd.Parameters.Add("@REQ_DATE", SqlDbType.Date, 20).Value = requesteddate;
        cmd.Parameters.Add("@REQ_TIME", SqlDbType.Time, 20).Value = requestedtime;
        cmd.Parameters.Add("@ATTENDANCE", SqlDbType.Int, 50).Value = attendance;
        cmd.Parameters.Add("@EVENT_TYPE", SqlDbType.NVarChar, 50).Value = eventtype;
        cmd.Parameters.Add("@OTHER_DESC", SqlDbType.NVarChar, 225).Value = other;
        cmd.Parameters.Add("@LEAD_SOURCE", SqlDbType.NVarChar, 50).Value = leadsource;
        cmd.Parameters.Add("@NOTES", SqlDbType.NVarChar, 225).Value = notes;
        cmd.Parameters.Add("@CATERING", SqlDbType.NVarChar, 1).Value = catering;
        cmd.Parameters.Add("@BAR", SqlDbType.NVarChar, 1).Value = bar;
        cmd.Parameters.Add("@DAMAGE_DEPOSIT", SqlDbType.NVarChar, 19).Value = damagedeposit;
        cmd.Parameters.Add("@DANCE_FLOOR", SqlDbType.Money).Value = Decimal.Parse(dancefloor);


        cmd.CommandType = CommandType.Text;
        cmd.ExecuteNonQuery();
    }
    catch (System.Data.SqlClient.SqlException ex_msg)
    {
        string msg = "Error occured while inserting";
        msg += ex_msg.Message;
        throw new Exception(msg);
    }
    finally
    {

        conn.Close();
    }
    try
    {
        conn.Open();
        SqlCommand cmd = new SqlCommand(sql2, conn);

        cmd.Parameters.Add("@NOTEDATE", SqlDbType.Date, 50).Value = griddate;
        cmd.Parameters.Add("@NOTEBY", SqlDbType.NVarChar, 50).Value = gridnotes;
        cmd.Parameters.Add("@COMMENTS", SqlDbType.NVarChar, 50).Value = comments;

        cmd.CommandType = CommandType.Text;
        cmd.ExecuteNonQuery();
    }
    catch (System.Data.SqlClient.SqlException ex_msg)
    {
        string msg = "Error occured while inserting";
        msg += ex_msg.Message;
        throw new Exception(msg);
    }
    finally
    {

        conn.Close();
    }

}
protected void Page_Load(object sender, EventArgs e)
{
    griddate.Text = DateTime.Now.ToString("yyyy/MM/dd");
}
protected void submit_Click(object sender, EventArgs e)
{
    if (requesteddate.Text == "")
    {
        Finish.Text = "Please complete the form!";
    }
    else if (requestedtime.Text == "")
    {
        Finish.Text = "Please complete the form!";
    }
    else if (attendance.Text == "")
    {
        Finish.Text = "Please complete the form!";
    }
    else
    {
        execution(eventspecialist.Text, phone.Text, phone2.Text, firstname.Text, lastname.Text, besttime.SelectedItem.Text, companyname.Text, nonprofit.Text, requesteddate.Text, requestedtime.Text, attendance.Text, eventtype.SelectedItem.Text, other.Text, leadsource.SelectedItem.Text, notes.Text, catering.Text, bar.Text, damagedeposit.Text, dancefloor.SelectedItem.Text, griddate.Text, gridnotes.SelectedItem.Text, comments.Text);
        Finish.Visible = false;
        conform.Visible = true;
    }
}

Answer 1

First column names and then variables

string sql = "INSERT INTO tblcontacts (Col1,Col2,...) VALUES (@Var1,@Var2,...)"