Hi we are using a console app to import data from a database to Umbraco to create product nodes. But am struggling to set the TeaCommerce stock level of products.

When i try update a product like so:

IProductService productService = ProductService.Instance;
productService.SetStock(1, "658480", 10m);

I get an exception {"Value cannot be null.\r\nParameter name: context"}

with stacktrace

  at Autofac.ResolutionExtensions.ResolveService(IComponentContext context, Service service, IEnumerable`1 parameters)
   at Autofac.ResolutionExtensions.Resolve(IComponentContext context, Type serviceType, IEnumerable`1 parameters)
   at Autofac.ResolutionExtensions.Resolve[TService](IComponentContext context, IEnumerable`1 parameters)
   at Autofac.ResolutionExtensions.Resolve[TService](IComponentContext context)
   at TeaCommerce.Api.Services.ProductService.get_Instance()
   at DataImporter.Program.Main(String[] args) in e:\Program.cs:line 55

can anyone help? how am i supposed to set Tea commerce stock levels as part of a bulk import?