I ordered a host of Tamiya parts a little while back from RCMarket that showed out of stock along with some parts in stock.
They emailed to confirm that some parts were out of stock so could not ship them and offered the chance to cancel the order for those parts. I said I wasn't desperate for those parts so left the order on.
Within about 10 days more emails to confirm shipping and then items arrived shortly afterwards. Can't fault the service really!