Cannot insert information in SQL database

I'm developing a website for a parent association, for a school. My system has two reserved areas, which parents and also teachers/school members has access. These two areas, are the backoffice and the FrontOffice.

I can begin a new session with a dad or mother username, and their respective password, and then in frontoffice i've a new page where, it was supossed, a new meal be sucessfully done reserved and in result of that a new row should be inserted in a SQL database table.

It happens that for this, i've next code:

 protected void ReserveMeal (object sender, EventArgs e)
        {
            string tipoRefeicao=string.Empty;
            DateTime DataSelecionada = Convert.ToDateTime(BasicDatePicker1.Text.ToString());
            bool refeicaoFinalizada = false; //Refeicao nao é consumida no imediato 

            try
            {

                //ligar a base de dados e realizar nova conexao
                SqlConnection con = new SqlConnection(@"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=C:\Users\Vitor\Documents\Visual Studio 2015\Projects\Educational\Educational\App_Data\SchoolPASS.mdf; Integrated Security=True;Connect Timeout=30");
                con.Open();
                string selectUser = "SELECT count (*) from EEAluno where NomeUtilizadorEE='" + newName + "'";
                string res = Convert.ToString(selectUser);
                SqlCommand com = new SqlCommand(selectUser, con);
                int temp = Convert.ToInt32(com.ExecuteScalar().ToString());
                con.Close();
                if (temp == 1)
                {
                    con.Open();
                    string verificaPassword = "select Password from EEAluno where NomeUtilizadorEE='" + newName + "'";
                    SqlCommand passCommand = new SqlCommand(verificaPassword, con);
                    string password = passCommand.ExecuteScalar().ToString();
                    if (password == Session["Pass"].ToString())//Nao testado
                    {
                        //Inserir refeicao numa tabela nova
                        SqlCommand insert = new SqlCommand("INSERT INTO TabelaRefeicoesEncomendadas (NomePessoa,TipoRefeicao,Data, Finalizada) VALUES (@NomePessoa,@TipoRefeicao,@Data,@Finalizada)", con);
                        //insert.Parameters.Add("@Id", 1);
                        insert.Parameters.AddWithValue("@NomePessoa", newName);
                        insert.Parameters.AddWithValue("@TipoRefeicao", tipoRefeicao);
                        insert.Parameters.AddWithValue("@Data", DataSelecionada);
                        insert.Parameters.AddWithValue("@Finalizada", refeicaoFinalizada);//escreve falso na DB

                    }

                }
            }
            catch (Exception exc)
            {

            }


        }

Doing a carefully analysis, in code, you could observe that i'm, trying to check if the autenticated user is the correct user.

So if we have many users inside a DB table, only one, only for example "X" (i assumed that "X" has sucessfully logged into system), is the active user, in a determined computer, and only "X" could reserve a meal for the respective children.

Resume: I've thinked in a algorithm to check the user session, and then insert a reserved meal, into a database table. I did not succeed. I think it can not verify correctly the sessions. Two errors exist.

1. Every time that i try to create the meal (when method is called), the username is incremented, so if username is "X" username becomes "XX"
2. The information about meal is not inserted into SQL database.

Could you help me!