C# If Else Statement Return Different MessageBox Errors

I want to Show messages with MessageBox.Show() Method.

If txt_Phone.TextLength >= 3 AND dtp_StartDate.Value < dtp_EndDate.Value they do same thing. But I want to show different messages. For textlength I will show 'Enter more than 3 characters.' For if startdate greater than stopdate I will show ' Start Date can not bigger than Stop Date'

 if (txt_Phone.TextLength >= 3 & dtp_StartDate.Value < dtp_EndDate.Value)
            {
                DataTable dt = new DataTable();
                SqlConnection myConn = new SqlConnection("Data Source=***;Initial Catalog=ViasesTest;User Id=sa;Password=****;MultipleActiveResultSets=true;");
                myConn.Open();
                SqlCommand myCmd = new SqlCommand("sp_GetData", myConn);
                myCmd.Parameters.AddWithValue("@StartDate", dtp_StartDate.Value.ToString("yyyy-MM-dd HH:mm:ss"));
                myCmd.Parameters.AddWithValue("@EndDate", dtp_EndDate.Value.ToString("yyyy-MM-dd HH:mm:ss"));
                myCmd.Parameters.AddWithValue("@Phone", txt_Phone.Text.ToString().Trim());
                myCmd.CommandType = CommandType.StoredProcedure;
                SqlDataAdapter da = new SqlDataAdapter(myCmd);
                da.Fill(dt);
                dataGridView1.DataSource = dt;
            }
            else
            {
                MessageBox.Show("Hata!");
            }