Stored Procedure Not working from c# code

Question

I'm trying to call a stored procedure within C#.

using (SqlConnection connection = new SqlConnection(connectionString))
   using (SqlCommand command = connection.CreateCommand())
    {
      command.CommandType = CommandType.StoredProcedure;
      command.CommandText = "updateData";
      command.Parameters.Add(new SqlParameter("@inrego", rego));
      command.Parameters.Add(new SqlParameter("@inOprt", oprt));
      command.Parameters.Add(new SqlParameter("@inService", service));

      connection.Open();

      int update = command.ExecuteNonQuery();

      Console.WriteLine(update);

      connection.Close();
    }

update shows 1 on console, but the database still isn't updated.

This is the stored procedure

CREATE PROCEDURE [dbo].updateData
@inrego varchar(5),
@inOprt char(3),
@inService as varchar(50)

AS
delete from buses where rego = @inrego;
insert into buses (rego, operator,service) values(@inrego, @inOprt, @inService);
RETURN 0

Running the stored procedure manually works, aka

USE [C:\USERS\---\DOCUMENTS\VISUAL STUDIO 2013\PROJECTS\---\TEST.DB.MDF]
GO

DECLARE @return_value Int

EXEC    @return_value = [dbo].[updateData]
        @inrego = N'1',
        @inOprt = N'2',
        @inService = N'3'

SELECT  @return_value as 'Return Value'

GO

works, and successfully updates the database, but the code form C# doesn't.

Answer 1

I have been unable to reproduce the issue on clean local database(MS SQL EXPRESS 2013, Win 8.1, .NET 4.5):

CREATE TABLE [dbo].buses
(
    [rego] varchar(5) NOT NULL PRIMARY KEY,
    [operator] char(3),
    [service] varchar(50)
)

static void UpdateOrInsertBuses(String rego, String oprt, String service)
{
    using (SqlConnection connection = new SqlConnection(connectionString))
    {
        using (SqlCommand command = connection.CreateCommand())
        {
            command.CommandType = CommandType.StoredProcedure;
            command.CommandText = "updateData";
            command.Parameters.Add(new SqlParameter("@inrego", rego));
            command.Parameters.Add(new SqlParameter("@inOprt", oprt));
            command.Parameters.Add(new SqlParameter("@inService", service));

            connection.Open();
            try
            {
                int update = command.ExecuteNonQuery();

                Console.WriteLine(update);
            }
            catch (Exception exc)
            {
                Console.WriteLine(exc.Message);
            }
            finally
            {
                connection.Close();
            }
        }
    }
}

// ...
// Add data
UpdateOrInsertBuses("11", "12", "13");
UpdateOrInsertBuses("21", "22", "23");

// Update added
UpdateOrInsertBuses("21", "22", "Changed for sure");

So, it is some issue that does not relate to your current code. As it has been suggested by @ Gordon Linoff it is either a permission issue, or some trigger that meddles into the updates, or the database for some reasons reverts or ignores any changes.