The object is not defined as an instance of an object in rhinos

update: 3

I am trying to make fun of the method that a class uses to create new instances of other classes through a unit of work. When I try and mock a method to return fixed data, I get zero instead of a list when the getPage method was called.

here is my code

[TestFixture()]
public class CustomerServiceTests
{
    private ICustomerService service;
    private IUnitOfWork mockUnitOfWork;
    private IGenericRepository<Entities.Customer> repository;

    private int customerId;
    private int ContactId;

    [SetUp()]
    public void Setup()
    {
        customerId = 1;
        ContactId = 1;
    }

  [Test()]
    public void GetCustomers_should_return_three_results()
    {
        mockUnitOfWork = MockRepository.GenerateMock<IUnitOfWork>();
        repository = MockRepository.GenerateMock<IGenericRepository<Entities.Customer>>();

        List<Entities.Customer> customerList = new List<Entities.Customer>
        {
            new Entities.Customer { Id = 1, CompanyName = "test1", ContractorId = 1 },
            new Entities.Customer { Id = 2, CompanyName = "test2", ContractorId = 2 },
            new Entities.Customer { Id = 3, CompanyName = "test3", ContractorId = 1 },
            new Entities.Customer { Id = 4, CompanyName = "test4", ContractorId = 1 },
            new Entities.Customer { Id = 5, CompanyName = "test5", ContractorId = 4 }
        };


        var IQueryableList = customerList.AsEnumerable();            
        mockUnitOfWork.Stub(uow => uow.CustomerRepository).Return(repository);




        repository.Stub(repo => repo.GetPaged()).Return(new ContentList<Entities.Customer> { List = IQueryableList, Total = customerList.Count });

        service = new CustomerService(mockUnitOfWork);

        var resultList = service.GetCustomers(new PageRequest {PageSize = 20, PageIndex = 1 });
        var total = resultList.Data.Total;
        Assert.AreEqual(10, total);
    }

Part of the utility code returns null instead of a list.

            customers = _service.CustomerRepository.GetPaged(filter, orderBy, pageRequest.PageSize, pageRequest.PageIndex, "CustomersContacts");