The MS Store full stop is appalling. The site completely screwed over my original 950xl order, and customer support firstly said that Firefox would be responsible for the webstore adding up the cost of phone and shipping wrong by over ?100! They then couldn't fix payment requests when the site duplicated my order, their only response, even at "the highest levels of escalation" was wait and see. Then they told me I was incorrect when I told them that Amazon was taking pre-orders including tax & next day shipping for the same amount MS was charging excluding tax & shipping. Even when I sent them a link they insisted it was incorrect and excluded tax. They kept on ignoring everything until I cancelled the order.
Interestingly they are also trying to blame Amazon for their (UK) shipping delay, even when I pointed out that Clove, Argos and Expansys were also quoting delays from Microsoft, they insisted it was the local retailers fault....